Should work now for emails

It should valid every RFC valid emails.
A regex from a comment somewhere on a website, don't remember where but
I kept it (no licence on it, shared freely)

service/user/form/form_validator.go

@@ -7,7 +7,8 @@ import (
 	msg "github.com/NyaaPantsu/nyaa/util/messages"
 )
 
-const emailRegex = `(\w[-._\w]*\w@\w[-._\w]*\w\.\w{2,3})`
+// Regex by: Philippe Verdy (in a comment somewhere on a website) - Valid every email RFC valid
+const emailRegex = `^((?:[-!#$%&'*+/=?^` + "`" + `{|}~\w]|\\.)+(?:\.(?:[-!#$%&'*+/=?^` + "`" + `{|}~\w]|\\.)+)*|"(?:[^\\"]|\\.)+")@(?:\[(?:((?:(?:[01][\d]{0,2}|2(?:[0-4]\d?|5[0-5]?|[6-9])?|[3-9]\d?)\.){3}(?:[01][\d]{0,2}|2(?:[0-4]\d?|5[0-5]?|[6-9])?|[3-9]\d?))|IPv6:((?:[0-9A-F]{1,4}:){7}[0-9A-F]{1,4}|(?:[0-9A-F]{1,4}:){6}:[0-9A-F]{1,4}|(?:[0-9A-F]{1,4}:){5}:(?:[0-9A-F]{1,4}:)?[0-9A-F]{1,4}|(?:[0-9A-F]{1,4}:){4}:(?:[0-9A-F]{1,4}:){0,2}[0-9A-F]{1,4}|(?:[0-9A-F]{1,4}:){3}:(?:[0-9A-F]{1,4}:){0,3}[0-9A-F]{1,4}|(?:[0-9A-F]{1,4}:){2}:(?:[0-9A-F]{1,4}:){0,4}[0-9A-F]{1,4}|[0-9A-F]{1,4}::(?:[0-9A-F]{1,4}:){0,5}[0-9A-F]{1,4}|::(?:[0-9A-F]{1,4}:){0,6}[0-9A-F]{1,4}|(?:[0-9A-F]{1,4}:){1,7}:|(?:[0-9A-F]{1,4}:){6}(?:(?:[01][\d]{0,2}|2(?:[0-4]\d?|5[0-5]?|[6-9])?|[3-9]\d?)\.){3}(?:[01][\d]{0,2}|2(?:[0-4]\d?|5[0-5]?|[6-9])?|[3-9]\d?)|(?:[0-9A-F]{1,4}:){0,5}:(?:(?:[01][\d]{0,2}|2(?:[0-4]\d?|5[0-5]?|[6-9])?|[3-9]\d?)\.){3}(?:[01][\d]{0,2}|2(?:[0-4]\d?|5[0-5]?|[6-9])?|[3-9]\d?)|::(?:[0-9A-F]{1,4}:){0,5}(?:(?:[01][\d]{0,2}|2(?:[0-4]\d?|5[0-5]?|[6-9])?|[3-9]\d?)\.){3}(?:[01][\d]{0,2}|2(?:[0-4]\d?|5[0-5]?|[6-9])?|[3-9]\d?))|([-a-z\d]{0,62}[a-z\d]:[^\[\\\]]+))\]|([a-z\d](?:[-a-z\d]{0,62}[a-z\d])?(?:\.[a-z\d](?:[-a-z\d]{0,62}[a-z\d])?)+))$`
 const usernameRegex = `(\W)`
 
 // EmailValidation : Check if an email is valid