Getting error when trying to git push to remote branch (Heroku)
Your push command is to remote heroku-production but your pull command is to origin. The non-fast-foward message means the history in your current repo differs from the Heroku remote; likely someone has pushed a branch with some merges or rebases.
I implore you to not use Heroku as the authoritative git remote. Assuming you are not, you can force push over the Heroku master branch to resolve this.
git push -f heroku-production master:master