no implicit conversion of nil into String
 app/lib/firebase_wrapper.rb:113:in `+'


-------------------------------
Request:
-------------------------------

 * URL        : https://full-db.test.bikelink.org/people/31069/verify_phone
 * HTTP Method: POST
 * IP address : 98.35.154.160
 * Parameters : {"_method"=>"post", "authenticity_token"=>"7Y/TQi9sraWN2Bjv0iBAbOJkqacbQlLvriN4z8ykqEujkcb8els6jzpidJk2OfIVFn3x4xp0nG+7IpKMs1xvBw==", "controller"=>"people", "action"=>"verify_phone", "id"=>"31069"}
 * Timestamp  : 2021-03-31 18:08:53 UTC
 * Server : sites-2.test.bikelink.org
   * Rails root : /var/www/full-db
 * Process: 8541

-------------------------------
Session:
-------------------------------

 * session id: [FILTERED]
 * data: {"session_id"=>"42099ef902595f3c751062461f3d6744",
  "warden.user.person.key"=>[[31069], "sTS8Ej46w_WwHcSCjmQv"],
  "_csrf_token"=>"4e6gXOI5F6zGX6CHYS88/Wsu02KtWjlEaIC370uoFTk="}


-------------------------------
Backtrace:
-------------------------------

 app/lib/firebase_wrapper.rb:113:in `+'
 app/lib/firebase_wrapper.rb:113:in `push_notification'
 app/lib/firebase_wrapper.rb:50:in `user_phone_confirmed'
 app/models/person.rb:303:in `mark_phone_verified!'
 app/controllers/people_controller.rb:62:in `verify_phone'