Add a couple of Go questions

Also some contribution guidelines.

CONTRIBUTING.md

@@ -1 +1,17 @@
+## How to contribute
+
 Use pull requests to contribute to the project.
+
+Stick to the following format:
+
+<details>
+<summary>[Question]</summary><br><b>
+
+[Answer]
+</b></details>
+
+## What to avoid
+
+* Avoid adding installation questions. Those are the worst type of questions...
+* Don't copy questions and answers from other sources. They probably worked hard for adding them.
+* If you add new images, make sure they are free and can be used.