Coinbase uses OAuth2.
Register an application at Coinbase
Fill in the Client Id and Client Secret values in your settings:
SOCIAL_AUTH_COINBASE_KEY = ''
SOCIAL_AUTH_COINBASE_SECRET = ''
Set the redirect_url on coinbase. Make sure to include the trailing slash, eg. http://hostname/complete/coinbase/
Specify scopes with:
SOCIAL_AUTH_COINBASE_SCOPE = [...]
By default the scope is set to balance.