Fixed #31181 -- Added links to related models for admin's readonly fields.

tests/admin_views/models.py

@@ -365,6 +365,9 @@ class Language(models.Model):
     english_name = models.CharField(max_length=50)
     shortlist = models.BooleanField(default=False)
 
+    def __str__(self):
+        return self.iso
+
     class Meta:
         ordering = ('iso',)
 
@@ -999,3 +1002,9 @@ class UserProxy(User):
     """Proxy a model with a different app_label."""
     class Meta:
         proxy = True
+
+
+class ReadOnlyRelatedField(models.Model):
+    chapter = models.ForeignKey(Chapter, models.CASCADE)
+    language = models.ForeignKey(Language, models.CASCADE)
+    user = models.ForeignKey(User, models.CASCADE)