POWERSYNC prototype: add migration to create postgresql publication

wger/nutrition/migrations/0025_create_publication.py

@@ -0,0 +1,26 @@
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('nutrition', '0024_remove_ingredient_status'),
+    ]
+
+    operations = [
+        migrations.RunSQL(
+            """
+            DO $$
+            BEGIN
+                IF NOT EXISTS (
+                    SELECT 1 FROM pg_publication WHERE pubname = 'powersync'
+                ) THEN
+                    CREATE PUBLICATION powersync FOR TABLE nutrition_ingredient, auth_user;
+                END IF;
+            END $$;
+            """,
+            reverse_sql="""
+            DROP PUBLICATION IF EXISTS powersync;
+            """
+        ),
+    ]