adding explicit ember script

Author: Jake Goldsborough

package.json

@@ -12,7 +12,8 @@
     "start:local": "yarn run ember server --proxy http://127.0.0.1:8888",
     "start:staging": "yarn run ember server --proxy https://staging-crates-io.herokuapp.com",
     "start:live": "yarn run ember server --proxy https://crates.io",
-    "test": "yarn run ember test"
+    "test": "yarn run ember test",
+    "ember": "ember"
   },
   "repository": "",
   "engines": {