Finished the initial draft of upgrading instructions

readme.md

@@ -27,10 +27,21 @@ REQUIREMENTS
 The minimum requirement by Yii is that your Web server supports PHP 5.3.?.
 
 
+DOCUMENTATION
+-------------
+
+For 1.1 users, you may refer to [Upgrading from Yii 1.1](docs/guide/upgrade-from-v1.md)
+to have a general idea of what has changed in 2.0.
+
+We are writing more documentation to get you started and learn more in depth.
+
+
 HOW TO PARTICIPATE
 ------------------
 
-You are welcome to participate in Yii 2 development in the following ways:
+**Your participation to Yii 2 development is very welcome!**
+
+You may participate in the following ways:
 
 * [Report issues](https://github.com/yiisoft/yii2/issues)
 * [Give us feedback or start a design discussion](http://www.yiiframework.com/forum/index.php/forum/42-design-discussions-for-yii-20/)