Add GCM push for pushing OneMDM app to devices

app/models/app.rb

@@ -1,4 +1,11 @@
 class App < ActiveRecord::Base
 
+  has_many :batch_installations, dependent: :destroy
+  
   validates :name, :package_name, presence: true
+
+  def apk_url
+    return DEFAULT_APP_URL if self.package_name.eql?(DEFAULT_APP_PACKAGE_NAME)
+    ""
+  end
 end