Improve latter half of instructions for blog demo

[jrhorn424]

• Use curl scripts, not copy-pasta.
  • Write the scripts, put on master branch
• Make Comments and Posts protected
• Check not only /users, but /posts or /comments
  • Don't forget to log-in first

[Jcornmanhomonoff]

@jrhorn424 added :index to users controller to skip authentication. << Possible solution to your last bullet??