add sql to create library_item_labels db table

packages/db/migrations/0120.do.library_item_labels.sql

@@ -0,0 +1,13 @@
+-- Type: DO
+-- Name: library_item_labels
+-- Description: Create table library_item_labels
+
+BEGIN;
+
+CREATE TABLE omnivore.library_item_labels (
+    library_item_id uuid NOT NULL REFERENCES omnivore.library_item(id) ON DELETE CASCADE,
+    label_id uuid NOT NULL REFERENCES omnivore.labels(id) ON DELETE CASCADE,
+    PRIMARY KEY (library_item_id, label_id)
+);
+
+COMMIT;

packages/db/migrations/0120.undo.library_item_labels.sql

@@ -0,0 +1,9 @@
+-- Type: UNDO
+-- Name: library_item_labels
+-- Description: Create table library_item_labels
+
+BEGIN;
+
+DROP TABLE omnivore.library_item_labels;
+
+COMMIT;