'fewer than 80 characters' should be 'up to'
Merge pull request #130 from SirLenz0rlot/master

minor: up to 80 characters
added an advice about flat_map
mentioned rubocop
Improve English idiom. Also fix a few errors.
Merge pull request #131 from ruafozy/improve-1

Improve English idiom. Also fix a few errors.
added a title quotation to the regex section of the guide
nested the Annotations section under comments
fix #132 - fail is a method, not a keyword
Merge pull request #4 from bbatsov/master

Update