The Oxford Comma

Punctuation is important. There is a subtle difference between inviting the strippers, JFK, & Stalin; and inviting the strippers, JKF & Stalin.

Capitalisation is also important. There's a subtle difference between helping my Uncle Jack off a horse; and helping my uncle ...

Reduce the ambiguity of your project by adding this line to your application's Gemfile:

gem 'the_oxford_comma'

And then execute:

$ bundle

Or install it yourself as:

$ gem install the_oxford_comma

Just require the gem and you'll make any sane grammatist happy.

["the strippers", "Kennedy", "Stalin"].and
# => "the strippers, Kennedy, and Stalin"

["the strippers", "Kennedy", "Stalin"].or
# => "the strippers, Kennedy, or Stalin"    

Why not. Punctuation is important.

"By train, plane and sedan chair, Peter Ustinov retraces a journey made by Mark Twain a century ago. The highlights of his global tour include encounters with Nelson Mandela, an 800-year-old demigod and a dildo collector."

"Top stories today: World leaders attend Mandela tribute, Obama and Castro meet and same-sex marriage date set."