Hello, could someone point me in the right direct.  I wanted to integrate social logins and i set everything up but now i cant seem to work out the callback uri script, in the instructions it says:  
2. Implement the callback script

Once the user has selected a social network (like for example Facebook), he will be asked to sign in with this account. If the user successfully authenticates, he will be redirected to the callback_uri that you specified in the plugin parameters.

The callback_uri is an URL to a script on your server. This script contains a few lines of code that extract the POST parameter connection_token and fetch the user profile data by sending a request to our API Connections Resource.

So my question is where is this callback script is it a script within oxwall or does it reside on the sever its self.  Iam new to this any help would be appreciated thanks