title: Check if a string is all-capitals in Rails
body: <p>I'm looking to check if a string is all capitals in Rails.
  How would I go about doing that?</p>
  
  <p>I'm writing my own custom pluralize helper method and I would something be passing words like "WORD" and sometimes "Word" - I want to test if my word is all caps so I can return "WORDS" - with a capital "S" in the end if the word is plural (vs. "WORDs").</p>
  
  <p>Thanks!</p>