update(web_api): index more created_at based queries (#794)

technically we only need to index:
  - github_event.created_at
  - user_pull_request_activity_progress.created_at
  - pul_request_activity_progress.created_at

but it was easier to update the parent class instead of
the specific ones.

web_api/web_api/migrations/0026_auto_20220322_0036.py

@@ -0,0 +1,53 @@
+# Generated by Django 3.0.3 on 2022-03-22 00:36
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("web_api", "0025_auto_20200902_0052"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="account",
+            name="created_at",
+            field=models.DateTimeField(auto_now_add=True, db_index=True),
+        ),
+        migrations.AlterField(
+            model_name="accountmembership",
+            name="created_at",
+            field=models.DateTimeField(auto_now_add=True, db_index=True),
+        ),
+        migrations.AlterField(
+            model_name="githubevent",
+            name="created_at",
+            field=models.DateTimeField(auto_now_add=True, db_index=True),
+        ),
+        migrations.AlterField(
+            model_name="pullrequestactivity",
+            name="created_at",
+            field=models.DateTimeField(auto_now_add=True, db_index=True),
+        ),
+        migrations.AlterField(
+            model_name="pullrequestactivityprogress",
+            name="created_at",
+            field=models.DateTimeField(auto_now_add=True, db_index=True),
+        ),
+        migrations.AlterField(
+            model_name="user",
+            name="created_at",
+            field=models.DateTimeField(auto_now_add=True, db_index=True),
+        ),
+        migrations.AlterField(
+            model_name="userpullrequestactivity",
+            name="created_at",
+            field=models.DateTimeField(auto_now_add=True, db_index=True),
+        ),
+        migrations.AlterField(
+            model_name="userpullrequestactivityprogress",
+            name="created_at",
+            field=models.DateTimeField(auto_now_add=True, db_index=True),
+        ),
+    ]

web_api/web_api/models.py

@@ -53,7 +53,7 @@ def _repr(self: object) -> str:
 
 class BaseModel(models.Model):
     id = models.UUIDField(primary_key=True, default=uuid.uuid4)
-    created_at = models.DateTimeField(auto_now_add=True)
+    created_at = models.DateTimeField(auto_now_add=True, db_index=True)
     modified_at = models.DateTimeField(auto_now=True)
 
     class Meta: