Add method to Model Vote and function for statics_per_user in lib
Add new test user
Add test for statistics_per_user
Add function for API
Add API
Change per with by and fix minor issues
Change get_vote_user with get_votes_user
Add statistics link to user card
Change minor in API and frontend
add username to .mak file
Remove erroneous characters.
Fix the tests.

@yograterol added himself to the test data but didn't
update the test cases... ;)