ADD: rate limiting

package-lock.json

@@ -1476,6 +1476,11 @@
         }
       }
     },
+    "clone": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/clone/-/clone-1.0.4.tgz",
+      "integrity": "sha1-2jCcwmPfFZlMaIypAheco8fNfH4="
+    },
     "cluster-key-slot": {
       "version": "1.0.12",
       "resolved": "https://registry.npmjs.org/cluster-key-slot/-/cluster-key-slot-1.0.12.tgz",
@@ -1691,6 +1696,14 @@
       "resolved": "https://registry.npmjs.org/deep-is/-/deep-is-0.1.3.tgz",
       "integrity": "sha1-s2nW+128E+7PUk+RsHD+7cNXzzQ="
     },
+    "defaults": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/defaults/-/defaults-1.0.3.tgz",
+      "integrity": "sha1-xlYFHpgX2f8I7YgUd/P+QBnz730=",
+      "requires": {
+        "clone": "^1.0.2"
+      }
+    },
     "define-property": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/define-property/-/define-property-2.0.2.tgz",
@@ -2138,6 +2151,14 @@
         "vary": "~1.1.2"
       }
     },
+    "express-rate-limit": {
+      "version": "3.4.0",
+      "resolved": "https://registry.npmjs.org/express-rate-limit/-/express-rate-limit-3.4.0.tgz",
+      "integrity": "sha512-SktWQGHhTQfIOZykiVIaoqmHCptqq177fEbumVytWsMpEqe+g78IFrfzivJTimoCdMZ5+vYJ5/a/w1darXMv+A==",
+      "requires": {
+        "defaults": "^1.0.3"
+      }
+    },
     "extend": {
       "version": "3.0.2",
       "resolved": "https://registry.npmjs.org/extend/-/extend-3.0.2.tgz",