Thanks Simon for the reply. So, should I redirect the user to this?
https://forums.gemsociety.org/session/sso_login?sso=bm9uY2U9ZTU3NWU3YzI2ODM2MjEzYjNmZTNmZWE5ZTc4NjNiNTQmcmV0dXJu%250BX3Nzb191cmw9aHR0cCUzQSUyRiUyRmZvcnVtcy5nZW1zb2NpZXR5Lm9yZyUy%250BRnNlc3Npb24lMkZzc29fbG9naW4%253D%250B%26sig%3D9c9ee72cd56218de3fb5ba46b985084369874fc5f434afdb1d9b5d14d170c0a
When I do this, I get a blank screen in Discourse.