monitor http user games pagination

app/controllers/User.scala

@@ -139,6 +139,7 @@ object User extends LilaController {
     })(fuccess) flatMap { filterName =>
       val ip = HTTPRequest lastRemoteAddress ctx.req
       UserGamesRateLimitPerIP(ip, cost = page, msg = ip) {
+        lila.mon.http.userGames.cost(page)
         GameFilterMenu.paginatorOf(
           userGameSearch = userGameSearch,
           user = u,

modules/common/src/main/mon.scala

@@ -44,6 +44,9 @@ object mon {
     object mailgun {
       val timeout = inc("http.mailgun.timeout")
     }
+    object userGames {
+      def cost = incX(s"http.user-games.cost")
+    }
   }
   object lobby {
     object hook {