Add column for game outcome (#208)

Author: Askaholic

migrations/V80__store_game_outcomes.sql

@@ -0,0 +1,4 @@
+ALTER TABLE game_player_stats
+  ADD COLUMN result ENUM(
+    'VICTORY', 'DEFEAT', 'DRAW', 'MUTUAL_DRAW', 'UNKNOWN', 'CONFLICTING'
+  ) default 'UNKNOWN';