Removed unused dependency

package.json

@@ -20,7 +20,6 @@
     "gm": "^1.23.0",
     "knex": "^0.12.6",
     "multer": "^1.2.1",
-    "node-thumbnail": "^0.7.0",
     "randomstring": "^1.1.5",
     "sqlite3": "^3.1.8"
   }