直播增加级别限制

app/models/live_broad.rb

@@ -20,7 +20,7 @@ class LiveBroad < ActiveRecord::Base
           end
         end
       end
-      self.rank_strs="'#{self.rank_str.join("','")}'"
+      self.rank_strs="'#{self.rank_str.join("', '")}'"
     end
 
     IMG_STORE_PATH = "live_broads"