Ok thats weird, I definitely checked the git config file previously and it had bare set to true. I'm totally sure of it!
Also people including myself have been able to push commits to this repo previously. The command you issued returned false, so I rechecked the git config file and bare was set to false. I set it to true and pushed, problem solved!
git config --bool core.bare
#returned false
The config file must have been edited at some point without my knowledge.