plataformatec/devise — pull request #3392 by fauxparse (2014-12-29 23:20:55+00:00)
Title: If email is case-insensitive, uniqueness should be validated accordingly.

The default configuration for Devise is to treat email addresses as case-insensitive. However, when their uniqueness is validated, they are treated case-sensitively. This could lead to confusion.

This patch checks the "case_insensitive_keys" option when creating the validation.