Email in lowercase

[ihsaan-ullah]

@Didayolo

Description

• On signup emails are stored as lowercased to not allow users to create multiple accounts using the same email but in different cases
• White list emails are now checked in lower case to avoid any inconsistencies

Issues this PR resolves

• 🔥 Whitelist emails are leaked from API & should be case-insensitive #1766

A checklist for hand testing

• signup with a dummy uppercased email e.g. [email protected] and check in your profile that it is stored as [email protected]
• Add [email protected] to a competition whitelist and check that when you join the competition with [email protected] it approves you automatically

Checklist

• Code review by me
• Hand tested by me
• I'm proud of my work
• Code review by reviewer
• Hand tested by reviewer
• CircleCi tests are passing
• Ready to merge

[hzxie]

Thanks for creating this PR.