invalid param triggers 500 - should trigger 400

Started GET "/context/page?posts=1'A=0" for 127.0.0.1 at 2017-08-14 08:20:28 +0000
Processing by WikiPageController#show as HTML
  Parameters: {"posts"=>"1'A=0", "context_id"=>"context", "id"=>"page"}
Completed 500 Internal Server Error in 6ms (ActiveRecord: 2.8ms)

ArgumentError (invalid value for Integer(): "1'A=0"):
  app/models/page/comments.rb:22:in `posts'
  app/controllers/page/before_filters.rb:74:in `load_posts'
  app/controllers/dispatch_controller.rb:15:in `dispatch'