Use heroku-api gem and process commands in parallel for each heorku app via fork child processes 

Remove dependency to 'heroku' gem. 
Use 'heorku-api' gem to run commands. 
Parallelize commands to be run on multiple heorku apps: 
  bundle exec rake company1:staging company2:development heroku:deploy
  Will create 2 forked child processes each running against a different heroku app.