Add .pgpass file

[stevage]

Following information here: https://github.com/mapbox/tilemill/issues/2301#issuecomment-41951162

[stevage]

Remove old passwords like this:

perl -pi -e 's/"user": "gis",/"user": "gis"/g' project.mml
perl -pi -e 's/"password": ".*"//g' project.mml