There are two choices. The first is to develop your own token URL in your server-side coding language of choice and write some functionality which would authenticate your user to your system. You would then update the janrain.settings.tokenUrl value with the path to that token URL.
janrain.settings.tokenUrl = 'REPLACE_WITH_YOUR_TOKEN_URL';
The second choice which will be easier is to use a Janrain Engage plugin or widget written for your content management system or framework, which would handle most of the implementation for you. It looks like you are using web2py, which should have Janrain Engage (it's referred to by its old name, RPX) support already built in. Look through your documentation for more info.