Migrate old, locationless activities

src/main/resources/db/migration/V25__migrate_old_locationless_data.sql

@@ -0,0 +1,18 @@
+UPDATE activities a
+SET activity_location =
+        concat(
+                COALESCE(
+                        NULLIF(g.name_4, ''),
+                        NULLIF(g.name_3, ''),
+                        NULLIF(g.name_2, '')
+                ),
+                ', ',
+                g.name_0
+        )
+    FROM gadm_410 g
+WHERE a.activity_location IS NULL
+  AND a.simplified_track IS NOT NULL
+  AND ST_Intersects(
+    g.geom,
+    ST_SetSRID(ST_StartPoint(a.simplified_track), 4326)
+    );