Added collaboration

Author: tcorral

README.md

@@ -25,6 +25,10 @@ This repository contains a folder by each design pattern.
 Inside these folders you can found, in some of them, other folders with numbers . This folders are the different steps to follow to arrive to the final resolution of the problem.
 You will understand it better if you have one copy of the book I recomend you before.
 
+## Do you want to collaborate?
+
+All constructive comments are welcome. I promise I will answer everyone.
+
 ## Agreements
 
 [Head First Design Patterns](http://www.amazon.com/First-Design-Patterns-Elisabeth-Freeman/dp/0596007124/ref=sr_1_1?ie=UTF8&qid=1316512770&sr=8-1)