Fix for foreign key check regarding m2m

Some of the behavior changed between Django 3.2 and 4.2 so we make a fix
here to get around it. Also add the rule pk to the __str__ for us to use
while debugging

promgen/forms.py

@@ -153,6 +153,14 @@ def clean(self):
         super().clean()
         rule = models.Rule(**self.cleaned_data)
 
+        # In Django https://code.djangoproject.com/ticket/19580, some of the
+        # foreign key checks got stricter. We sets pk to 0 here so that it passes
+        # django's m2m/foreign key checks, but marks for us that it's a temporary
+        # rule that doesn't actually exist.
+        # We'll likely want to rework this assumption when we move to a different
+        # promql check
+        rule.pk = 0
+
         # Make sure we pull in our labels and annotations for
         # testing if needed
         # See django docs on cached_property

promgen/models.py

@@ -423,9 +423,9 @@ class Meta:
 
     def __str__(self):
         return (
-            f"{self.name}"
+            f"{self.pk}:{self.name}"
             if self.content_object is None
-            else f"{self.name} [{self.content_object.name}]"
+            else f"{self.pk}:{self.name} [{self.content_object.name}]"
         )
 
     def get_absolute_url(self):