fix typo

ttadmin/users/forms.py

@@ -22,7 +22,7 @@ def validate_username(username):
     if len(username) < USERNAME_MIN_LENGTH:
         raise ValidationError('Username too short.')
     if not USERNAME_RE.match(username):
-        raise ValidationError('Username must be all lowercase, start with a letter, and only use the _ special charcter')
+        raise ValidationError('Username must be all lowercase, start with a letter, and only use the _ special character')
     duplicate = Townie.objects.filter(username=username).count()
     if duplicate > 0:
         raise ValidationError('Username already in use :(')