Add licensing information

Author: sebromero

README.md

@@ -4,7 +4,9 @@ This repository hosts content for the documentation section of the Arduino Pro w
 
 # How Can I Contribute?
 
-Contributing by creating content or suggestion changes to existing content can be done by making pull requests. You start by forking the `master` branch. Create a new branch based on master and name it according to what you will create (e.g. `wifi-tutorial`). Make a copy of the `template` folder and modify that if you're creating a new document.
+Contributing by creating content or suggestion changes to existing content can be done by making pull requests. CC-BY-SA-4.0 is the default license for any contribution. Sample code within this documentation is made available under the CC0 license.
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+You start by forking the `master` branch. Create a new branch based on master and name it according to what you will create (e.g. `wifi-tutorial`). Make a copy of the `template` folder and modify that if you're creating a new document.
 
 When you're done with a draft you can create a pull request. This will give the content team the possibility to review it and leave comments or request changes. During this review process you can continue to push commits to the same branch. They will show up in the pull request automatically. Once the pull request gests merged into master, the content will be deployed to the staging server where you will be able to have a final look on how it looks on the website. When everything looks fine, one of the repository maintainers will create a release of the latest version. This will then be automatically deployed to the production server.