'Last known event date' as alias for planned_closure, closes #438

Also a migration which covers some recent model metadata changes

vaccinate/core/migrations/0108_availabilitytag_planned_closure_report_source.py

@@ -0,0 +1,40 @@
+# Generated by Django 3.1.8 on 2021-04-28 17:25
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("core", "0107_decimal_for_latitude_longitude"),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name="availabilitytag",
+            options={"ordering": ["-group", "name"]},
+        ),
+        migrations.AlterField(
+            model_name="report",
+            name="planned_closure",
+            field=models.DateField(
+                blank=True,
+                help_text='Date this site a site plans to stop operating, "planned_closure" in our API',
+                null=True,
+                verbose_name="Last known event date",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="report",
+            name="report_source",
+            field=models.CharField(
+                choices=[
+                    ("ca", "Caller app"),
+                    ("dc", "Data corrections"),
+                    ("wb", "Web banking"),
+                ],
+                default="ca",
+                max_length=2,
+            ),
+        ),
+    ]

vaccinate/core/models.py

@@ -610,7 +610,10 @@ class ReportSource(models.TextChoices):
         blank=True, null=True, help_text="Update for hours information"
     )
     planned_closure = models.DateField(
-        blank=True, null=True, help_text="Date this site a site plans to stop operating"
+        blank=True,
+        null=True,
+        help_text='Date this site a site plans to stop operating, "planned_closure" in our API',
+        verbose_name="Last known event date",
     )
     reported_by = models.ForeignKey(
         Reporter, related_name="reports", on_delete=models.PROTECT