Ruby : Files and Serialization : Format unreadable article in assignment

[XAJX179]

Because

The article linked is poorly formatted.

This PR

• Adds a links to a pastebin of well formatted version of article.
• Advises to use Odin Project's Markdown Preview tool on it.

Issue

Closes #XXXXX

Additional Information

the article was very hard to read so i decided to format it correctly for myself and now am just sharing it with other students :)

Pull Request Requirements

• [x] I have thoroughly read and understand The Odin Project curriculum contributing guide
• [x] The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• [x] The Because section summarizes the reason for this PR
• [x] The This PR section has a bullet point list describing the changes in this PR
• [x] If this PR addresses an open issue, it is linked in the Issue section
• [x] If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• [x] If any lesson files are included in this PR, they follow the Layout Style Guide