Updated config.py (#40)

Added RethinkDB config vars;
Removed PostgreSQL config vars;
Cleaned and grouped rest of config vars.
Updated requirements.txt (#40)

Added RethinkDB related packages;
Removed PostgreSQL related packages;
Updated and grouped rest of packages.
Updated manage.py database commands (#40)

Database-related commands in manage.py are now adapted to RethinkDB;
Changed also how RethinkDB is initialized app-wide.
Pluralized tables in manage.py (#40)

Database tables are now created by pluralizing their corresponding
model names.
Implemented RethinkDB in user model (#40)
Implemented RethinkDB in artist model (#40)
Implemented RethinkDB in user_artist model (#40)
Implemented RethinkDB in song model (#40)
Implemented RethinkDB in suggestion model (#40)
Added blueprints for API endpoints (#40)

Moved API endpoint views to /views and created blueprints for them.
Removed any trace of how this was done before.
Got rid of SQL database wrapper (#40)
Removed old tests (#40)

New tests are pending…will be written as soon as possible.
PEP8-compliant changes (#40)
Properly Facebook exception catching (#40)

Facebook exceptions are now properly caught and proper JSON responses
are built upon them.
Updated Flask-RethinkDB requirement (#40)
Fixed /suggest endpoint return value (#40)

The /suggest API endpoint now properly returns a dict in the ‘data’
key, instead of a single element list containing a dict.
Limited number of calls to /suggest endpoint (#40)

Limited the number of calls to the /suggest API endpoint, since it can
sometimes take quite a long time to fetch a suggestion.
Temporary fix for limiting number of calls to /suggest endpoint (#40)

Since limiting the number of calls using a decorator isn’t stable
enough, changed the way calls are limited using a ‘calls’ argument to
the ‘suggest’ endpoint function.