added initial introduction on README

Author: alexoah

README.md

@@ -1,2 +1,9 @@
-# CSharpPlayground
-A playground for C# programming language.
+# Alexoah's C# Playground
+A collection of C# programming language exercises.  
+Thank you for your visit!
+
+## List of Exercises
+* [W3School's C# Exercises](./W3School-CSExercises): answers to W3School's C# Exercises
+
+##
+<sup>:octocat: Created by [@alexoah](http://github.com/alexoah) at GitHub.</sup>