Handle some of the error cases with github login.

endpoints/api.py

@@ -72,13 +72,8 @@ def create_user_api():
     send_confirmation_email(new_user.username, new_user.email, code.code)
     return make_response('Created', 201)
   except model.DataModelException as ex:
-    message = ex.message
-    m = re.search('column ([a-zA-Z]+) is not unique', message)
-    if m and m.group(1):
-      message = m.group(1) + ' already exists'
-
     error_resp = jsonify({
-      'message': message,
+      'message': ex.message,
     })
     error_resp.status_code = 400
     return error_resp