fix: resolved a bug that references WidgetUser to the models of the forum app

widget_group_17/forum/models.py

 from django.db import models
+from homepage.models import WidgetUser
 
 # Create your models here.
 class Post(models.Model):
-    author = models.ForeignKey('homepage.WidgetUser', on_delete=models.CASCADE)
+    author = models.ForeignKey(WidgetUser, on_delete=models.CASCADE)
     post_title = models.CharField(max_length=100)
     post_body = models.CharField(max_length=1000)
     pub_date = models.DateTimeField("Date published")
 
 class Reply(models.Model):
-    author = models.ForeignKey('homepage.WidgetUser', on_delete=models.CASCADE)
+    author = models.ForeignKey(WidgetUser, on_delete=models.CASCADE)
     reply_body = models.CharField(max_length=1000)
     pub_date = models.DateTimeField("Replied on")