add node engine to package.json and call checkNodeVersion function in cli (#88)

global-cli/index.js

@@ -112,6 +112,8 @@ function run(root, appName, version, verbose) {
       return;
     }
 
+    checkNodeVersion();
+
     var scriptsPath = path.resolve(
       process.cwd(),
       'node_modules',
@@ -157,5 +159,6 @@ function checkNodeVersion() {
       process.version,
       packageJson.engines.node
     );
+    process.exit(1);
   }
 }

package.json

@@ -4,6 +4,9 @@
   "description": "Configuration and scripts for Create React App.",
   "repository": "facebookincubator/create-react-app",
   "license": "BSD-3-Clause",
+  "engines": {
+    "node": ">=4"
+  },
   "bugs": {
     "url": "https://github.com/facebookincubator/create-react-app/issues"
   },