Added intro to rails to the Curriculum nav bar
Merge branch 'master' of https://github.com/railsbridge-boston/railsbridge-boston
Re-added link to Create Heroku Account page
Added a link to pre_workshop page with vagrant install instructions in case participant didn't install them
Merge branch 'master' of https://github.com/railsbridge-boston/railsbridge-boston
Changed directions to create ~/workspace through Finder/File Explorer
and drag virtual box into it.  Less back and forth, groups the
command line steps together.