Add active column to matches table.
Add date field to add-match form.
Add missing 'form' request parameter to POST request.
Add match type picker, as first step in adding new match.
Move geenric match creation to /match/add/campaign location.
Add matches_campaign table. When creating new match, create record also
in matches_campaign table.
Add difficulty-level-picker in add-match form.
Add restarts field to add-match form.