Improve db

#8 @gsathya @ben-jones 
I changed directory structure and split server.py into models and views.
That would a fine replacement. This takes in strings with the names of different roles and creates links between the user and the roles. Basically, you specify strings like "admin" or "vpn" in the roles, then SQLAlchemy looks up the roles and creates links between the user and the roles when it creates the row for the user.