Fix non-numbers being passed to Redis and causing an error (#11697)

app/models/feed.rb

@@ -9,6 +9,11 @@ class Feed
   end
 
   def get(limit, max_id = nil, since_id = nil, min_id = nil)
+    limit    = limit.to_i
+    max_id   = max_id.to_i if max_id.present?
+    since_id = since_id.to_i if since_id.present?
+    min_id   = min_id.to_i if min_id.present?
+
     from_redis(limit, max_id, since_id, min_id)
   end