I had issues installing Postgres with the instructions in this Railscast. However I was able to get postgres running on my project with http://postgresapp.com/ and http://inductionapp.com/ (Hat tip to this stackoverflow thread).
- Download & install Postgres.app (documentation) Make sure to install in
/Applications. - Update your
PATH
In my case I added the following to ~/.bash_profile
export PATH="/Applications/Postgres.app/Contents/MacOS/bin:$PATH"
Check that Postgres.app is being loaded
$ which psql
/Applications/Postgres.app/Contents/MacOS/bin/psql