Below plist should go into ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
. LaunchAgent should pick it up on restart.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">