diff --git a/src/main/entities/base.ts b/src/main/entities/base-entity.ts
similarity index 80%
rename from src/main/entities/base.ts
rename to src/main/entities/base-entity.ts
index 7ae3f46..d7e07da 100644
--- a/src/main/entities/base.ts
+++ b/src/main/entities/base-entity.ts
@@ -1,7 +1,7 @@
 import { Entity, PrimaryGeneratedColumn } from 'typeorm';
 
 @Entity()
-export abstract class Base {
+export class BaseEntity {
   @PrimaryGeneratedColumn()
   public id: number;
 }
diff --git a/src/main/entities/library/author.ts b/src/main/entities/library/author.ts
index 0cf1875..aefb8f1 100644
--- a/src/main/entities/library/author.ts
+++ b/src/main/entities/library/author.ts
@@ -1,9 +1,10 @@
 import { Entity, ManyToMany } from 'typeorm';
+import { BaseEntity } from '../base-entity';
 import { MultiNamed } from './base/multi-named';
 import { Book } from './book';
 
 @Entity()
-export class Author extends MultiNamed {
+export class Author extends MultiNamed(BaseEntity) {
   @ManyToMany(() => Book, {
     nullable: false,
     onDelete: 'CASCADE',
diff --git a/src/main/entities/library/base/multi-named.ts b/src/main/entities/library/base/multi-named.ts
index f3d8fd3..330b993 100644
--- a/src/main/entities/library/base/multi-named.ts
+++ b/src/main/entities/library/base/multi-named.ts
@@ -1,11 +1,14 @@
 import { Column, Entity } from 'typeorm';
-import { Base } from '../../base';
 
-@Entity()
-export abstract class MultiNamed extends Base {
-  @Column()
-  public nameCanonical: string;
+export function MultiNamed<T extends Constructor>(BaseClass: T) {
+  @Entity()
+  class MixinClass extends BaseClass {
+    @Column()
+    public nameCanonical: string;
 
-  @Column('simple-array')
-  public names: string[];
+    @Column('simple-array')
+    public names: string[];
+  }
+
+  return MixinClass;
 }
diff --git a/src/main/entities/library/base/rateable.ts b/src/main/entities/library/base/rateable.ts
new file mode 100644
index 0000000..3a1647e
--- /dev/null
+++ b/src/main/entities/library/base/rateable.ts
@@ -0,0 +1,11 @@
+import { Column, Entity } from 'typeorm';
+
+export function Rateable<T extends Constructor>(BaseClass: T) {
+  @Entity()
+  class MixinClass extends BaseClass {
+    @Column({ nullable: true })
+    public rating: number;
+  }
+
+  return MixinClass;
+}
diff --git a/src/main/entities/library/base/tslint.json b/src/main/entities/library/base/tslint.json
new file mode 100644
index 0000000..4770a4d
--- /dev/null
+++ b/src/main/entities/library/base/tslint.json
@@ -0,0 +1,6 @@
+{
+  "extends": ["../../../../../tslint.json"],
+  "rules": {
+    "typedef": false
+  }
+}
diff --git a/src/main/entities/library/book.ts b/src/main/entities/library/book.ts
index e398feb..e8163be 100644
--- a/src/main/entities/library/book.ts
+++ b/src/main/entities/library/book.ts
@@ -1,13 +1,15 @@
 import { Entity, JoinTable, ManyToMany, OneToMany } from 'typeorm';
+import { BaseEntity } from '../base-entity';
 import { Author } from './author';
 import { MultiNamed } from './base/multi-named';
+import { Rateable } from './base/rateable';
 import { Character } from './character';
 import { Copy } from './copy';
 import { Fiction } from './fiction';
 import { Tag } from './tag';
 
 @Entity()
-export class Book extends MultiNamed {
+export class Book extends Rateable(MultiNamed(BaseEntity)) {
   @OneToMany(
     () => Copy,
     (copy: Copy) => copy.original,
diff --git a/src/main/entities/library/character.ts b/src/main/entities/library/character.ts
index 5f464b1..88c2f37 100644
--- a/src/main/entities/library/character.ts
+++ b/src/main/entities/library/character.ts
@@ -1,10 +1,11 @@
 import { Entity, ManyToMany } from 'typeorm';
+import { BaseEntity } from '../base-entity';
 import { MultiNamed } from './base/multi-named';
 import { Book } from './book';
 import { Fiction } from './fiction';
 
 @Entity()
-export class Character extends MultiNamed {
+export class Character extends MultiNamed(BaseEntity) {
   @ManyToMany(() => Book, {
     nullable: false,
     onDelete: 'CASCADE',
diff --git a/src/main/entities/library/copy-type.ts b/src/main/entities/library/copy-type.ts
index 7c82edb..ea1232c 100644
--- a/src/main/entities/library/copy-type.ts
+++ b/src/main/entities/library/copy-type.ts
@@ -1,5 +1,5 @@
 import { Column, Entity, ManyToOne } from 'typeorm';
-import { Base } from '../base';
+import { BaseEntity } from '../base-entity';
 import { Copy } from './copy';
 
 const enum CopyTypes {
@@ -10,7 +10,7 @@ const enum CopyTypes {
 }
 
 @Entity()
-export class CopyType extends Base {
+export class CopyType extends BaseEntity {
   @ManyToOne(
     () => Copy,
     (copy: Copy) => copy.types,
diff --git a/src/main/entities/library/copy.ts b/src/main/entities/library/copy.ts
index 24819e5..0ceeec8 100644
--- a/src/main/entities/library/copy.ts
+++ b/src/main/entities/library/copy.ts
@@ -1,5 +1,6 @@
 import { Column, Entity, JoinTable, ManyToMany, ManyToOne, OneToMany } from 'typeorm';
-import { Base } from '../base';
+import { BaseEntity } from '../base-entity';
+import { Rateable } from './base/rateable';
 import { Book } from './book';
 import { CopyType } from './copy-type';
 import { Language } from './language';
@@ -7,7 +8,7 @@ import { Source } from './source';
 import { Translator } from './translator';
 
 @Entity()
-export class Copy extends Base {
+export class Copy extends Rateable(BaseEntity) {
   @ManyToOne(
     () => Book,
     (book: Book) => book.copies,
diff --git a/src/main/entities/library/fiction.ts b/src/main/entities/library/fiction.ts
index d67d3b0..8fd8745 100644
--- a/src/main/entities/library/fiction.ts
+++ b/src/main/entities/library/fiction.ts
@@ -1,10 +1,11 @@
 import { Entity, ManyToMany } from 'typeorm';
+import { BaseEntity } from '../base-entity';
 import { MultiNamed } from './base/multi-named';
 import { Book } from './book';
 import { Character } from './character';
 
 @Entity()
-export class Fiction extends MultiNamed {
+export class Fiction extends MultiNamed(BaseEntity) {
   @ManyToMany(() => Book, {
     nullable: false,
     onDelete: 'CASCADE',
diff --git a/src/main/entities/library/language.ts b/src/main/entities/library/language.ts
index 2deaa2b..3e6b532 100644
--- a/src/main/entities/library/language.ts
+++ b/src/main/entities/library/language.ts
@@ -1,9 +1,9 @@
 import { Column, Entity, ManyToMany } from 'typeorm';
-import { Base } from '../base';
+import { BaseEntity } from '../base-entity';
 import { Copy } from './copy';
 
 @Entity()
-export class Language extends Base {
+export class Language extends BaseEntity {
   @Column({
     nullable: false,
     unique: true,
diff --git a/src/main/entities/library/site.ts b/src/main/entities/library/site.ts
index c78061b..bcdf75c 100644
--- a/src/main/entities/library/site.ts
+++ b/src/main/entities/library/site.ts
@@ -1,9 +1,10 @@
 import { Entity, OneToMany } from 'typeorm';
+import { BaseEntity } from '../base-entity';
 import { MultiNamed } from './base/multi-named';
 import { Source } from './source';
 
 @Entity()
-export class Site extends MultiNamed {
+export class Site extends MultiNamed(BaseEntity) {
   @OneToMany(
     () => Source,
     (source: Source) => source.site,
diff --git a/src/main/entities/library/source.ts b/src/main/entities/library/source.ts
index f1ccef7..2c91327 100644
--- a/src/main/entities/library/source.ts
+++ b/src/main/entities/library/source.ts
@@ -1,10 +1,10 @@
 import { Column, Entity, ManyToMany, ManyToOne } from 'typeorm';
-import { Base } from '../base';
+import { BaseEntity } from '../base-entity';
 import { Copy } from './copy';
 import { Site } from './site';
 
 @Entity()
-export class Source extends Base {
+export class Source extends BaseEntity {
   @Column({
     nullable: false,
     unique: true,
diff --git a/src/main/entities/library/tag.ts b/src/main/entities/library/tag.ts
index cd8a473..266e85a 100644
--- a/src/main/entities/library/tag.ts
+++ b/src/main/entities/library/tag.ts
@@ -1,9 +1,10 @@
 import { Entity, ManyToMany } from 'typeorm';
+import { BaseEntity } from '../base-entity';
 import { MultiNamed } from './base/multi-named';
 import { Book } from './book';
 
 @Entity()
-export class Tag extends MultiNamed {
+export class Tag extends MultiNamed(BaseEntity) {
   @ManyToMany(() => Book, {
     nullable: false,
     onDelete: 'CASCADE',
diff --git a/src/main/entities/library/translator.ts b/src/main/entities/library/translator.ts
index eb3ddf3..7e13de9 100644
--- a/src/main/entities/library/translator.ts
+++ b/src/main/entities/library/translator.ts
@@ -1,9 +1,10 @@
 import { Entity, ManyToMany } from 'typeorm';
+import { BaseEntity } from '../base-entity';
 import { MultiNamed } from './base/multi-named';
 import { Copy } from './copy';
 
 @Entity()
-export class Translator extends MultiNamed {
+export class Translator extends MultiNamed(BaseEntity) {
   @ManyToMany(() => Copy, {
     nullable: false,
     onDelete: 'CASCADE',
diff --git a/src/main/migrations/library/1574452206367-add_rating.ts b/src/main/migrations/library/1574452206367-add_rating.ts
new file mode 100644
index 0000000..c63ce9e
--- /dev/null
+++ b/src/main/migrations/library/1574452206367-add_rating.ts
@@ -0,0 +1,51 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class addRating1574452206367 implements MigrationInterface {
+  name = 'addRating1574452206367';
+
+  public async up(queryRunner: QueryRunner): Promise<any> {
+    await queryRunner.query(
+      `CREATE TABLE "temporary_copy" ("id" integer PRIMARY KEY AUTOINCREMENT NOT NULL, "favorited" boolean NOT NULL DEFAULT (0), "isDigital" boolean NOT NULL, "originalId" integer NOT NULL, "rating" integer, CONSTRAINT "FK_e8ce0011cf0a8b9fdc8ad908a44" FOREIGN KEY ("originalId") REFERENCES "book" ("id") ON DELETE CASCADE ON UPDATE CASCADE)`,
+      undefined
+    );
+    await queryRunner.query(
+      `INSERT INTO "temporary_copy"("id", "favorited", "isDigital", "originalId") SELECT "id", "favorited", "isDigital", "originalId" FROM "copy"`,
+      undefined
+    );
+    await queryRunner.query(`DROP TABLE "copy"`, undefined);
+    await queryRunner.query(`ALTER TABLE "temporary_copy" RENAME TO "copy"`, undefined);
+    await queryRunner.query(
+      `CREATE TABLE "temporary_book" ("id" integer PRIMARY KEY AUTOINCREMENT NOT NULL, "nameCanonical" varchar NOT NULL, "names" text NOT NULL, "rating" integer)`,
+      undefined
+    );
+    await queryRunner.query(
+      `INSERT INTO "temporary_book"("id", "nameCanonical", "names") SELECT "id", "nameCanonical", "names" FROM "book"`,
+      undefined
+    );
+    await queryRunner.query(`DROP TABLE "book"`, undefined);
+    await queryRunner.query(`ALTER TABLE "temporary_book" RENAME TO "book"`, undefined);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<any> {
+    await queryRunner.query(`ALTER TABLE "book" RENAME TO "temporary_book"`, undefined);
+    await queryRunner.query(
+      `CREATE TABLE "book" ("id" integer PRIMARY KEY AUTOINCREMENT NOT NULL, "nameCanonical" varchar NOT NULL, "names" text NOT NULL)`,
+      undefined
+    );
+    await queryRunner.query(
+      `INSERT INTO "book"("id", "nameCanonical", "names") SELECT "id", "nameCanonical", "names" FROM "temporary_book"`,
+      undefined
+    );
+    await queryRunner.query(`DROP TABLE "temporary_book"`, undefined);
+    await queryRunner.query(`ALTER TABLE "copy" RENAME TO "temporary_copy"`, undefined);
+    await queryRunner.query(
+      `CREATE TABLE "copy" ("id" integer PRIMARY KEY AUTOINCREMENT NOT NULL, "favorited" boolean NOT NULL DEFAULT (0), "isDigital" boolean NOT NULL, "originalId" integer NOT NULL, CONSTRAINT "FK_e8ce0011cf0a8b9fdc8ad908a44" FOREIGN KEY ("originalId") REFERENCES "book" ("id") ON DELETE CASCADE ON UPDATE CASCADE)`,
+      undefined
+    );
+    await queryRunner.query(
+      `INSERT INTO "copy"("id", "favorited", "isDigital", "originalId") SELECT "id", "favorited", "isDigital", "originalId" FROM "temporary_copy"`,
+      undefined
+    );
+    await queryRunner.query(`DROP TABLE "temporary_copy"`, undefined);
+  }
+}
diff --git a/src/main/migrations/library/tslint.json b/src/main/migrations/library/tslint.json
new file mode 100644
index 0000000..0b4e3a4
--- /dev/null
+++ b/src/main/migrations/library/tslint.json
@@ -0,0 +1,8 @@
+{
+  "extends": ["../../../../tslint.json"],
+  "rules": {
+    "class-name": false,
+    "member-access": false,
+    "typedef": false
+  }
+}
diff --git a/src/types/constructor.ts b/src/types/constructor.ts
new file mode 100644
index 0000000..c83a5f3
--- /dev/null
+++ b/src/types/constructor.ts
@@ -0,0 +1 @@
+type Constructor<T = {}> = new (...args: any[]) => T;