rails-server: add page

[nelsonfigueroa]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR title conforms to the recommended templates.

[tldr-bot]

The build for this PR failed with the following error(s):

pages/common/rails-server.md:24:21 MD047/single-trailing-newline Files should end with a single newline character
pages/common/rails-server.md:1: TLDR009 Page should contain a newline at end of file

Please fix the error(s) and push again.

[gutjuri]

Which pages does thhis server serve? The current directory, such as python -m http.server?

[nelsonfigueroa]

Which pages does thhis server serve? The current directory, such as python -m http.server?

@gutjuri Yeah it's the current directory. Maybe I can update the description at the top? Something like: "Serve the Rails app in the current directory using the Puma web server, which comes bundled with Rails."

[nelsonfigueroa]

Thanks for the review everyone. This should be good to go now.