diff --git a/package.json b/package.json
index 88707f8..8d44d55 100644
--- a/package.json
+++ b/package.json
@@ -30,6 +30,7 @@
     "sinon": "~1.17.3"
   },
   "dependencies": {
+    "bluebird": "~3.3.5",
     "debug": "~2.2.0",
     "elasticsearch": "~11.0.1",
     "lodash": "~4.11.1",