create new heroku app

setup.sh

heroku accounts:add account_name --auto
ssh-keygen -t rsa -C "emailaddresshere"

# add the ssh config file with heroku config to ~/.ssh/config file
Host heroku.com
  HostName heroku.com
  IdentityFile home/username/.ssh/identity.heroku.account_name
  IdentitiesOnly yes

#set new account as current
heroku accounts:set account_name 
#to add the keys
heroku keys:add ~/.ssh/identity.heroku.account_name.pub