fix(auth0): ensure user_id is set in user profile

fixes #476

lib/common/user/Auth0Manager.js

@@ -83,6 +83,13 @@ class Auth0Manager {
           profile.accessToken = accessToken
           // set data expiration timestamp to be 60 seconds into the future
           profile.dataExpirationTimestamp = (new Date()).getTime() + 60000
+          // The user_id might not be provided in certain cases, so try to use
+          // the `sub` field instead.
+          // See https://community.auth0.com/t/missing-user-id-from-user-profile/11457/7
+          profile.user_id = profile.user_id || profile.sub
+          if (!profile.user_id) {
+            return reject(new Error('Could not determine user_id for user!'))
+          }
           setProfile(profile)
           resolve(profile)
         }