Clarification about wrong username

[cyberb]

Username regex failure does not explain what exactly is wrong.
For example this config which users do not see fails on first capital case letter:

USERNAME_REGEX="^[a-z][a-zA-Z0-9\._-]{1,32}$"

Message is username is invalid.

Unless there is a library to explain regex failures which is user friendly probably the simplest thing is to add another field:

USERNAME_REGEX_MESSAGE="should start with lower case letter; contain only letters, numbers, dot, underscore or dash; be less than 32 characters"

[wheelybird]

Hi. Yes, that's a good idea. I'll add that in the next release.