Update admin user settings

app/api/schemas.py

@@ -2,7 +2,6 @@ from apifairy.fields import FileField
 from marshmallow import validate, validates, ValidationError
 from marshmallow.decorators import post_dump
 from app import ma
-from app.auth import USERNAME_REGEX
 from app.models import (
     Job,
     JobStatus,
@@ -142,7 +141,10 @@ class UserSchema(ma.SQLAlchemySchema):
     username = ma.auto_field(
         validate=[
             validate.Length(min=1, max=64),
-            validate.Regexp(USERNAME_REGEX, error='Usernames must have only letters, numbers, dots or underscores')
+            validate.Regexp(
+                User.username_pattern,
+                error='Usernames must have only letters, numbers, dots or underscores'
+            )
         ]
     )
     email = ma.auto_field(validate=validate.Email())