When using MySQL as database backend in GitLab, ``date`` in ``date(created_at), count(id) as total_amount``
won't return the ``date`` column (should be ``date(created_at)``), as a result, there's no contribution in the user
profile page.
Adding an ``as date`` can solve this problem.
* count opening of issues and merge requests
* dont trigger git repository - use events from database
* much-much faster since does not affected by repository size
