* Downgrade alpine from edge to 3.7, where libressl is 2.6 (needed for
openssl crate) and almost everything is more robust.
* Copy to the container only required files.
* Add libgcc package.
* Add readme file.
Listen port and database URL can be configured by using
environment variables: IPTOASN_PORT AND IPTOASN_DBURL
Docker container for the iptoasn_webservice may be used as a
binary - arbitrary args will be passed to the service if supplied
Aloïs Micard