Add SB Curated (copied from the smartbugs repository).

dataset/unchecked_low_level_calls/lotto.sol

@@ -0,0 +1,29 @@
+/*
+ * @source: https://github.com/sigp/solidity-security-blog
+ * @author: Suhabe Bugrara
+ * @vulnerable_at_lines: 20,27
+ */
+
+ pragma solidity ^0.4.18;
+ 
+ contract Lotto {
+
+     bool public payedOut = false;
+     address public winner;
+     uint public winAmount;
+
+     // ... extra functionality here
+
+     function sendToWinner() public {
+         require(!payedOut);
+         // <yes> <report> UNCHECKED_LL_CALLS
+         winner.send(winAmount);
+         payedOut = true;
+     }
+
+     function withdrawLeftOver() public {
+         require(payedOut);
+         // <yes> <report> UNCHECKED_LL_CALLS
+         msg.sender.send(this.balance);
+     }
+ }