added flash message to username change

app/logic.py

@@ -22,6 +22,7 @@ def home():
         if username:
             nusern_dbcall = User.query.filter_by(id=current_user.id).first()
             nusern_dbcall.username = username
+            flash('Username updated!', category='success')
         elif passwd and passwdc:
             if passwd == passwdc:
                 npasswd_dbcall = User.query.filter_by(id=current_user.id).first()