Change to PostgreSQL notes for Django 1.4

[Rohaq]

Hi,

You might want to add a note for the following page under PostgreSQL:
​https://docs.djangoproject.com/en/1.4/ref/databases/

I'm running PostgreSQL 9.1 locally, and found that Django was unable to connect to the database when the 'HOST' value was left as an empty string, resulting in the following error when running python manage.py syncdb:

psycopg2.OperationalError: FATAL:  Peer authentication failed for user

After some searching, I found the following solution on StackOverflow: ​http://stackoverflow.com/a/8232004/733402

Setting it to localhost rather than an empty string (as suggested by the inline comments in the config file) fixed the issue. You might want to consider adding this to the documentation so that other users can more easily work around the same issue.

Cheers!

-R

[Łukasz Rekucki]

The problem here is that psycopg2's default is a UNIX socket not an IP connection to localhost, which is what the comment in settings might suggest. I think it would be better to fix the settings.py template and/or change the driver to pass 'localhost' to psycopg2 by default.

[Claude Paroz]

-1 to set localhost by default.

Very roughly, here is what we could add:
"By default (empty HOST), the connection to the database is done through UNIX domain sockets ('local' lines in pg_hba.conf). If you want to connect through TCP sockets, set HOST to 'localhost' or '127.0.0.1' ('host' lines in pg_hba.conf). On Windows, you should always define HOST, as UNIX domain sockets are not available."

[Tim Graham <timograham@…>]

In 249c3d730e632b3c5b8c2bf5e6e871d61df15c6c:

Fixed #19090 - Added PostgreSQL connection note.

Thanks Melevir for the patch.

[Tim Graham <timograham@…>]

In 26e0651c42a70104d237b5433970158d27b244dc:

[1.5.X] Fixed #19090 - Added PostgreSQL connection note.

Thanks Melevir for the patch.

Backport of 249c3d730e from master