Show only recent organizers as partners

Our hompage shows the logos of some organizers that no longer participate in the SUL. Now only organizers that have an event in the last year are shown

championship/tests/test_index_page.py

@@ -105,13 +105,30 @@ class HomepageTestCase(TestCase):
         """
         Safety check to make sure we correctly have static files.
         """
-        EventOrganizerFactory(image="leonin_league.png")
+        organizer = EventOrganizerFactory(image="leonin_league.png")
+        EventFactory(organizer=organizer, date=datetime.date.today())
         response = self.client.get("/")
         self.assertIn("organizers", response.context)
         self.assertIn(
             "media/leonin_league.png", response.context["organizers"][0].image.url
         )
 
+    def test_images_only_shows_recent_organizers(self):
+        organizer = EventOrganizerFactory(image="leonin_league.png")
+        EventFactory(organizer=organizer, date=datetime.date.today())
+
+        organizer = EventOrganizerFactory(image="GBB.png")
+        EventFactory(
+            organizer=organizer,
+            date=datetime.date.today() - datetime.timedelta(days=365),
+        )
+
+        organizer = EventOrganizerFactory(image="lotus.png")
+
+        response = self.client.get("/")
+        self.assertIn("organizers", response.context)
+        self.assertEqual(len(response.context["organizers"]), 1)
+
     def test_no_open_invoice(self):
         """Checks that by default we don't have an open invoice."""
         response = self.client.get("/")