Update README.md

Author: SloMusti

README.md

@@ -29,3 +29,11 @@ for i in range(0, 1000):
         ppk2_test.average_of_sampling_period(read_data)
     time.sleep(0.01)
 ```
+
+
+## Licensing
+pp2-api-python is licensed under [GPL V2 license](https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html).
+
+What this means is that you can use this hardware and documentation without paying a royalty and knowing that you'll be able to use your version forever. You are also free to make changes but if you share these changes then you have to do so on the same conditions that you enjoy.
+
+IRNAS is name and mark of Institute IRNAS. You may use these name and terms only to attribute the appropriate entity as required by the Open Licence referred to above. You may not use them in any other way and in particular you may not use them to imply endorsement or authorization of any hardware that you design, make or sell.