Update README.md

Author: harro

README.md

@@ -65,3 +65,20 @@ Follow the instructions below for how to create new templates to display output
 
 There are opensource template repositories such as [ntc-templates](https://github.com/networktocode/ntc-templates)
 that provide structured output for many common commands.
+
+Before contributing
+-------------------
+If you are not a Google employee, our lawyers insist that you sign a Contributor
+Licence Agreement (CLA).
+
+If you are an individual writing original source code and you're sure you own
+the intellectual property, then you'll need to sign an
+[individual CLA](https://cla.developers.google.com/about/google-individual).
+Individual CLAs can be signed electronically. If you work for a company that
+wants to allow you to contribute your work, then you'll need to sign a
+[corporate CLA](https://cla.developers.google.com/clas).
+The Google CLA is based on Apache's. Note that unlike some projects
+(notably GNU projects), we do not require a transfer of copyright. You still own
+the patch.
+
+Sadly, even the smallest patch needs a CLA.