add object-assign polyfill

because older versions of node does not support native Object.assign

Author: gorangajic

lib/exec.js

@@ -1,5 +1,6 @@
 var spawn = require('child_process').spawn;
 var dotenv = require('./dot-env');
+var objectAssign = require('object-assign');
 
 module.exports = function exec(script) {
 
@@ -14,7 +15,7 @@ module.exports = function exec(script) {
 
 	script.env = script.env || {};
 
-	var env = Object.assign(process.env, script.env, dotenv);
+	var env = objectAssign(process.env, script.env, dotenv);
 
 	console.log('to be executed:', command, options.join(' '));
 	var command = spawn(command, options, {env: env});

package.json

@@ -20,7 +20,8 @@
     "test": "node index.js test --test"
   },
   "dependencies": {
-    "endofline": "0.0.3"
+    "endofline": "0.0.3",
+    "object-assign": "^4.0.1"
   },
   "betterScripts": {
     "test": {