Update contributing docs with "Get up to speed" section

This  adds  a  "Get up to speed"  section  to  the  Get  started
contributing  guide.  The  section  contains  links  to  Docker,
Kubernetes,  Go and Travis CI official docimentation  as well as
some interesting Golang blog posts and sources

Signed-off-by: Ivana Yovcheva (VMware) <[email protected]>

Author: ivanayov

docs/contributing/get-started.md

@@ -16,6 +16,21 @@ Before raising a PR or an issue request that you read our [Contributing guide](h
 
 * Improve the [OpenFaaS CLI tooling](https://github.com/openfaas/faas-cli) with a PR or documentation
 
+### Get up to speed
+
+If you are new with Docker, Kubernetes or Go and would like to learn or just improve your skills, you may find the following links useful:
+
+* [Docker Documentation](https://docs.docker.com)
+* [Kubernetes Documentation](https://kubernetes.io/docs/home/?path=browse)
+* Golang
+  - [The Go Programming Language](https://golang.org)
+  - [Go Documentation](https://golang.org/doc/)
+  - Alex Ellis' [golang basics](https://blog.alexellis.io/tag/golang-basics/) blog posts
+  - [The Case For Go](https://gist.github.com/ungerik/3731476) - a list of sources collected by Erik Unger
+  - Another interesting blog post - [Why should you learn Go?](https://medium.com/@kevalpatel2106/why-should-you-learn-go-f607681fad65) by Keval Patel
+  - Official Golang [GitHUb](https://github.com/golang) account
+* [Travis CI User Documentation](https://docs.travis-ci.com)
+
 ### Main Git repositories
 
 Git is used for version control and all repositories are public available under two organisations.