Where or function backport from Rails 5 for Rails 4.2

Confirm works from Rails 4.2.3 to 4.2.6, including for preloading, higher version may also works. Please create issue with your experience.

Installation:

gem 'where-or'

post = Post.where('id = 1').or(Post.where('id = 2'))

Largely copy from bf4 gist