Added search users by roles (e.g. 'is:hacker', 'is:forhire is:hacker') a...

...nd full text search on the user's bio by keywords (e.g. 'python backend developer'). Search by roles and keywords is also possible (e.g. 'is:hacker is:forhire python'). In order to test full text search on dev you need to connect to a PostgreSQL database.