Remove unused dependency `express`
diff --git a/package.json b/package.json
index 8b06ee3..71598cc 100644
--- a/package.json
+++ b/package.json
@@ -75,7 +75,6 @@
     "eslint-plugin-node": "^5.1.1",
     "eslint-plugin-promise": "^3.5.0",
     "eslint-plugin-standard": "^3.0.1",
-    "express": "^4.16.3",
     "grunt": "^1.0.1",
     "grunt-contrib-clean": "^1.0.0",
     "istanbul": "^0.4.5",