Merge branch 'core'

ExpCore/ranking.lua

@@ -159,6 +159,17 @@ function Ranking.give_rank(player,rank,by_player,tick)
             ['Reason:']='No Reason'
         }
     end
+    game.write_file('ranking.json',
+        table.json({
+            tick=tick,
+            play_time=player.online_time,
+            player_name=player.name,
+            by_player_name=by_player_name,
+            new_rank=rank.name,
+            old_rank=old_rank.name,
+            power_increase=(old_rank.power-rank.power)
+        })..'\n'
+    , true, 0)
 end
 
 --- Revert the last change to a players rank