Modified db_handler to query for author, requested_author, publications and user
Simplified db_handler logic. db_handler methods are called directly from the module and not through an instance of DBHandler
Added DB queries in SubscriptionHandler in order to handle the user subscriptions
Added a script to create database models and made other minor changes
Replaced ifs with exceptions
Added name and surname to author
Modified code to search for requested_authors in DB and then crawl for each one of them
Added a method which informs subscribed users about a new publication
Refactored code according to PEP8. Added code to catch some exceptions
Fixed a bug with session
Changed request_handler to flask. Modified architecture to be RESTful compatible
Added request handlers for authors, afiiliations