removed old serializer file
refactored histogram generation to use existing Hero.which_team method
moved hero win/loss logic into new boolean method
refactored fetching of last match sequence number into new class method
refactored that mess of a Match function into something more OO
removed outdated comment
cleaned up a bunch of old, unnecessary commenting
added more validations to hero model
added some new validations to the match model
added initial code to aggregate a list of recent matches for individual heroes