Add SB Curated (copied from the smartbugs repository).

dataset/arithmetic/insecure_transfer.sol

@@ -0,0 +1,21 @@
+/*
+ * @source: https://consensys.github.io/smart-contract-best-practices/known_attacks/#front-running-aka-transaction-ordering-dependence
+ * @author: consensys
+ * @vulnerable_at_lines: 18
+ */
+
+pragma solidity ^0.4.0;
+
+contract IntegerOverflowAdd {
+    mapping (address => uint256) public balanceOf;
+
+    // INSECURE
+    function transfer(address _to, uint256 _value) public{
+        /* Check if sender has balance */
+        require(balanceOf[msg.sender] >= _value);
+        balanceOf[msg.sender] -= _value;
+        // <yes> <report> ARITHMETIC
+        balanceOf[_to] += _value;
+}
+
+}