i create an app on ruby on rails with heroku
this app already exist online
now I try to push a new version of this one on heroku, but i have an issue.
i already update my ruby and rails version (because this one was an old one an not supported by heroku anymore)
now i have this kind of issue

So I have a Rails application that I am trying to push to Heroku. When I run git push heroku master, I get: