Add SB Curated (copied from the smartbugs repository).

dataset/denial_of_service/auction.sol

@@ -0,0 +1,29 @@
+/*
+ * @source: https://github.com/trailofbits/not-so-smart-contracts/blob/master/denial_of_service/auction.sol
+ * @author: -
+ * @vulnerable_at_lines: 23
+ */
+
+pragma solidity ^0.4.15;
+
+//Auction susceptible to DoS attack
+contract DosAuction {
+  address currentFrontrunner;
+  uint currentBid;
+
+  //Takes in bid, refunding the frontrunner if they are outbid
+  function bid() payable {
+    require(msg.value > currentBid);
+
+    //If the refund fails, the entire transaction reverts.
+    //Therefore a frontrunner who always fails will win
+    if (currentFrontrunner != 0) {
+      //E.g. if recipients fallback function is just revert()
+      // <yes> <report> DENIAL_OF_SERVICE
+      require(currentFrontrunner.send(currentBid));
+    }
+
+    currentFrontrunner = msg.sender;
+    currentBid         = msg.value;
+  }
+}