react-native-cli initial commit

A cli package that is responsible for:
* starting a new react-native project
* forwarding all other commands to a cli module in react-native
* currently cli.js knows how to start the webserver, in the future it may do things like build the app etc.

cli.js

@@ -0,0 +1,48 @@
+/**
+ * Copyright 2004-present Facebook. All Rights Reserved.
+ */
+
+'use strict';
+
+var spawn = require('child_process').spawn;
+var path = require('path');
+
+function printUsage() {
+  console.log([
+    'Usage: react-native <command>',
+    '',
+    'Commands:',
+    '  start: starts the webserver',
+  ].join('\n'));
+  process.exit(1);
+}
+
+function run() {
+  var args = process.argv.slice(2);
+  if (args.length === 0) {
+    printUsage();
+  }
+
+  switch (args[0]) {
+  case 'start':
+    spawn('sh', [
+      path.resolve(__dirname, 'packager', 'packager.sh'),
+      '--projectRoots',
+      process.cwd(),
+    ], {stdio: 'inherit'});
+    break;
+  default:
+    console.error('Command `%s` unrecognized', args[0]);
+    printUsage();
+  }
+  // Here goes any cli commands we need to
+}
+
+function init() {
+  spawn('sh', [path.resolve(__dirname, 'init.sh')], {stdio:'inherit'});
+}
+
+module.exports = {
+  run: run,
+  init: init,
+};