README.md Add license

Closes #5

Author: luzpaz

README.md

@@ -53,6 +53,7 @@ Wiki documentation will be available soon.
 For bugs please open a ticket in the [issue queue](https://github.com/JMG1/ExplodedAssembly/issues). For discussion please use the [dedicated Exploded Assembly thread](https://forum.freecadweb.org/viewtopic.php?f=24&t=9028) in the FreeCAD forums.
 
 #### License 
+GPLv2.0
 
 #### Author
 Javier Martínez @JMG1