Updated README.md with license information (#70)

Author: ivaylokenov

README.md

@@ -100,6 +100,18 @@ MyWebApi
 	.WithMessage("Some exception message");
 ```
 
+## License
+
+Code by Ivaylo Kenov. Copyright 2015 Ivaylo Kenov.
+This library is licensed under [GNU General Public License v3](https://tldrlegal.com/license/gnu-general-public-license-v3-(gpl-3)) (full terms and conditions [here](https://www.gnu.org/licenses/gpl.html). Basically:
+
+ - If you create software that uses GPL, you must license that software under GPL v3 (see [GPL FAQ](http://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL))
+ - If you create software that uses GPL, you must release your source code (see [GPL FAQ](http://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL))
+ - If you start with a GPL license, you cannot convert to another license.
+ - **You cannot include MyWebApi in a closed source distribution under this license**.
+
+If you have a really-coolish-and-nice open source or just closed source commercial project and you want to include MyWebApi in it, leave a question on the [issues page](https://github.com/ivaylokenov/MyWebApi/issues) and another license with the latest version of the library will be provided **free of charge** to you.
+ 
 ## Any questions, comments or additions?
 
 Leave an issue on the [issues page](https://github.com/ivaylokenov/MyWebApi/issues) or send a [pull request](https://github.com/ivaylokenov/MyWebApi/pulls).