I see, I usually do ruby development so the webserver is then usually running as my user on my development machine (obviously that is not the case in production

I see, I usually do ruby development so the webserver is then usually running as my user on my development machine (obviously that is not the case in production). In your case, then I would just change pg_hba to allow all local connections as shown by moe above. (I would not set any password though since that is normally not useful or necessary for local development).