don't allow blocklisted domains in Web, ActivityPub ids

for #597

activitypub.py

@@ -78,8 +78,8 @@ class ActivityPub(User, Protocol):
         assert util.is_web(id), f'{id} is not a URL'
         domain = util.domain_from_link(id)
         assert domain, 'missing domain'
-        assert util.domain_from_link(id) not in common.DOMAINS, \
-            f'{id} is a Bridgy Fed domain'
+        assert domain not in common.DOMAIN_BLOCKLIST, \
+            f'{id} is a blocked domain'
 
     def web_url(self):
         """Returns this user's web URL aka web_url, eg 'https://foo.com/'."""

web.py

@@ -69,7 +69,7 @@ class Web(User, Protocol):
         id = self.key.id()
         assert re.match(common.DOMAIN_RE, id)
         assert id.lower() == id, f'upper case is not allowed in Web key id: {id}'
-        assert id not in common.DOMAINS, f'{id} is a Bridgy Fed domain'
+        assert id not in common.DOMAIN_BLOCKLIST, f'{id} is a blocked domain'
 
     @classmethod
     def get_or_create(cls, id, **kwargs):