diff --git a/package.json b/package.json
index 94dd0a0..d74cba5 100644
--- a/package.json
+++ b/package.json
@@ -11,6 +11,7 @@
     "babel-runtime": "^6.20.0",
     "bcrypt": "^1.0.2",
     "commonmark": "^0.27.0",
+    "core-js": "^2.5.0",
     "jquery": "^2.2.4",
     "jquery-validation": "^1.16.0",
     "lodash": "^4.17.4",