Add the same reference to Denial of Service

Michael Colburn · bohendo · commit 34c0be040306 · 2018-10-04T08:49:07.000-04:00
diff --git a/denial_of_service/README.md b/denial_of_service/README.md
@@ -32,3 +32,4 @@ using `while` loop that exists when gas drops below certain threshold.
 
 - https://www.reddit.com/r/ethereum/comments/4ghzhv/governmentals_1100_eth_jackpot_payout_is_stuck/
 - https://github.com/ConsenSys/smart-contract-best-practices#dos-with-unexpected-revert
+- https://vessenes.com/ethereum-griefing-wallets-send-w-throw-considered-harmful/

Original file line number	Diff line number	Diff line change
@@ -32,3 +32,4 @@ using `while` loop that exists when gas drops below certain threshold.
`32`	`32`
`33`	`33`	`- https://www.reddit.com/r/ethereum/comments/4ghzhv/governmentals_1100_eth_jackpot_payout_is_stuck/`
`34`	`34`	`- https://github.com/ConsenSys/smart-contract-best-practices#dos-with-unexpected-revert`
	`35`	`+- https://vessenes.com/ethereum-griefing-wallets-send-w-throw-considered-harmful/`