How to use OR condition in ActiveRecord query

I want to grab all the users that either have an email as the one supplied or the first and last name. So for example:

users = User.where(:first_name => "James", :last_name => "Scott")

which will return all the users that have the first and last name of "James" & "Scott".

users = User.where(:email => "james@gmail.com")

which will return the user with the email as "james@gmail.com".

Is there a way to do a where clause to return either the users with the same first and last name and the user with the email that matches in one where query or do I need to do a merge on the 2 separate where clauses.