Getting Started Guide: post.rb -> Post
Merge pull request #12373 from francisgo/patch-6

Getting Started Guide: post.rb -> Post [ci skip]
[ci skip] Update scaffold output and change some words.

Scaffold output: add jbuilder, update timestamp (edge guide!)

Add some file breadcrumb (comment) to help reader find files.

Improve readability by adding some command outputs.

Thanks for great help from @senny.
Merge pull request #12338 from JuanitoFatas/generator

[ci skip] Update scaffold output and change some words.