E-mail address uniqueness check is case sensitive

[DavidMStraub]

I just noticed that using different case for the same e-mail address passes the uniqueness check. I think we should convert all e-mail addresses to lower case before storing them.

[Nick-Hall]

The local part of an email address is actually case sensitive. Strictly speaking you should keep the original case, but I don't think that this will cause a problem in practice.

[emyoulation]

Technically, the local part of an eMail address case sensitive according to RFC 5321. However, email service providers have opted to not follow this part of the specification because it created excessive support costs. (Instead they enforce case-sensitivity in Usernames and Passwords.)

It seems like case-sensitivity in the uniqueness check would similarly cause us extra support costs.