Install postgres

Set up Postgres to run at startup

Check if the directory ~/Library/LaunchAgents exists. Create it if it doesn’t exist.

Find the plist file that came with the postgres install. I found mine at /usr/local/Cellar/postgresql/9.3.4/homebrew.mxcl.postgresql.plist.

Copy the plist file to the LaunchAgents directory.

cp /usr/local/Cellar/postgresql/9.3.4/homebrew.mxcl.postgresql.plist ~/Library/LaunchAgents/

Now use launchctl to load the file using this command:

launchctl load -w homebrew.mxcl.postgresql.plist