Merge pull request #1403 from RyanB28/patch-1

Removed broken link

README.md

@@ -83,7 +83,6 @@ It's a great way to learn.
 #### Build your own `Blockchain / Cryptocurrency`
 
 * [**ATS**: _Functional Blockchain_](https://beta.observablehq.com/@galletti94/functional-blockchain)
-* [**C#**: _Programming The Blockchain in C#_](https://programmingblockchain.gitbooks.io/programmingblockchain/)
 * [**Crystal**: _Write your own blockchain and PoW algorithm using Crystal_](https://medium.com/@bradford_hamilton/write-your-own-blockchain-and-pow-algorithm-using-crystal-d53d5d9d0c52)
 * [**Go**: _Building Blockchain in Go_](https://jeiwan.net/posts/building-blockchain-in-go-part-1/)
 * [**Go**: _Code your own blockchain in less than 200 lines of Go_](https://medium.com/@mycoralhealth/code-your-own-blockchain-in-less-than-200-lines-of-go-e296282bcffc)