Change prepublish to prepare

Author: Robert Jackson

package.json

@@ -16,7 +16,7 @@
     "build": "ember build --environment=production",
     "lint": "tslint --project tsconfig.json",
     "problems": "tsc -p tsconfig.json --noEmit",
-    "prepublish": "npm run build",
+    "prepare": "npm run build",
     "serve": "ember serve",
     "test": "ember test",
     "test:server": "ember test --server"