Gracefully handle the user token already existing #142
Description
GitHub's API will complain if you try to create a authorization that already exists, giving back an HTTP 422 without the value of the token. What that means is that the user needs to track down the recorded token somewhere else, or regenerate it.
Right now it simply fails in this situation. It should present the user with their options and allow them to more gracefully recover.
Related to GH-141