Adding guide for forward and reverse proxy servers

[ebrahimbharmal007]

What roadmap does this PR target?

• Code Change
• Frontend Roadmap
• Backend Roadmap
• DevOps Roadmap
• All Roadmaps
• [Yes] Guides

Please acknowledge the items listed below

• [ Yes ] I have discussed this contribution and got a go-ahead in an issue before opening this pull request.
• [ Yes ] This is not a duplicate issue. I have searched and there is no existing issue for this.
• [ Yes] I understand that these roadmaps are highly opinionated. The purpose is to not to include everything out there in these roadmaps but to have everything that is most relevant today comparing to the other options listed.
• [ Yes] I have read the contribution docs before opening this PR.

Enter the details about the contribution

After reading all the roadmaps and guides i decided that i want to contribute as well. In your devOps roadmap there was a section in which forward and reverse proxies were mentioned so i though of writing a guide on it. In my guide i have covered:

• What is a proxy server?
• What is a forward proxy server?
• What is a reverse proxy server?
• What are the advantages and uses of these proxy servers?
• Summary and an analogy

I hope you will like my guide and if there are any mistakes you would contact me in order to correct them. I am a senior at University of Texas at Arlington and this is my first pull request. My email id is ebrahimbharmal00@gmail.com

[kamranahmedse]

Thanks @ebrahimbharmal007