First install YARD
gem install yard
The obvious step is to fork the rails source and simply perform
yardoc which is an alias to doing
yard doc. This will output the nicely YARD-formatted Rails API into the
If you wish to view, say the Rails API via your own local YARD server, simply perform
yard -n --single-db && yard server
Point your browser to http://localhost:8808 to view your Rails API documentation, all nicely YARD-formatted.