API now respects ?limit param as long as it's within 2x default limit

app/controllers/api_controller.rb

@@ -62,6 +62,11 @@ class ApiController < ApplicationController
     response.headers['Link'] = LinkHeader.new(links)
   end
 
+  def limit_param(default_limit)
+    return default_limit unless params[:limit]
+    [params[:limit].to_i.abs, default_limit * 2].min
+  end
+
   def current_resource_owner
     @current_user ||= User.find(doorkeeper_token.resource_owner_id) if doorkeeper_token
   end