Docker Compose, Django: role "_" does not exist

This happens because your pgsql db was launched without any envs. The pgsql docker image only uses the envs the first time you created the container, after that it won't recreate DB and users.

The solution is to remove the pgsql volume so next time you docker-compose up you will have a fresh db with envs read. Simple way to do it is docker-compose down -v

Change your env order like this.

POSTGRES_DB=teddycrepineau
POSTGRES_USER=teddycrepineau
POSTGRES_PASSWORD= 

I find it at this issue. I hope it works.