Allow users to change their usernames

[connorshea]

I've had two people ask me to change their usernames in the last few weeks and done it manually both times. This isn't really scalable, so I should probably implement it in a settings page.

The main things to keep track of:

• Change the user slug as well when changing their username
• Make it a one-time-only thing (flip a flag on their user) or make it once-a-year (a column would keep track of the last time they changed their username). This would be to prevent ban-evading (hard to report/ban someone if they keep changing their username) and impersonation.

The other thing I'd need to decide on is for URLs. It might be fine to just not preserve the redirect, I guess?

[darylf]

Great idea with applying a limit to how often you'd like to allow a user to make the change.

Other things to consider:

• Keep a history of the previous username(s) a user has had. This would help track down malicious historical behaviour.
• Set a limit on how soon after renaming the username, the old username can be reassigned/registered. This could help a user who accidentally changed their name and block someone else from quickly hijacking the username.