Fix issue with redirect_uri not identical between code and token phases (#7)

See:
omniauth/omniauth-oauth2#93
omniauth/omniauth-oauth2#93 (comment)
oauth-xx/oauth2#269

Author: neerfri

lib/omniauth/strategies/applicaster.rb

@@ -26,6 +26,10 @@ def raw_info
       def client
         ::Applicaster::Accounts.oauth_client
       end
+
+      def callback_url
+        full_host + script_name + callback_path
+      end
     end
   end
 end