[API] Implement notes/watching/

src/services/note/unwatch.ts

@@ -0,0 +1,9 @@
+import * as mongodb from 'mongodb';
+import Watching from '../../models/note-watching';
+
+export default async (me: mongodb.ObjectID, note: object) => {
+	await Watching.remove({
+		noteId: (note as any)._id,
+		userId: me
+	});
+};