made some basic structure changes and made some tests too

src/migrations/005_create-set-table.js

@@ -0,0 +1,22 @@
+export const up = (pgm) => {
+	pgm.sql(`
+          CREATE TABLE sets (
+            id UUID PRIMARY KEY,
+            collection_id UUID NOT NULL,
+            name TEXT NOT NULL,
+            location_id UUID,
+            image_id UUID,
+            created_at TIMESTAMP DEFAULT NOW(),
+            updated_at TIMESTAMP DEFAULT NOW(),
+            FOREIGN KEY (collection_id) REFERENCES collections(id),
+            FOREIGN KEY (location_id) REFERENCES locations(id),
+            FOREIGN KEY (image_id) REFERENCES images(id)
+          );
+        `)
+}
+
+export const down = (pgm) => {
+	pgm.sql(`
+        DROP TABLE sets;
+      `)
+}