touch
/Library/LaunchDaemons/com.mysql.mysql.plist

<?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">?
? <dict>?
??? <key>KeepAlive</key>?
??? <true/>?
??? <key>Label</key>?
??? <string>com.mysql.mysqld</string>?
??? <key>ProgramArguments</key>?
??? <array>?
??? <string>/usr/local/mysql/bin/mysqld_safe</string>?
??? <string>--user=root</string>?
??? </array>???
? </dict>?
</plist>?

sudo launchctl load -w /Library/LaunchDaemons/com.mysql.mysql.plist