Add SB Curated (copied from the smartbugs repository).

dataset/arithmetic/timelock.sol

@@ -0,0 +1,32 @@
+/*
+ * @source: https://github.com/sigp/solidity-security-blog
+ * @author: -
+ * @vulnerable_at_lines: 22
+ */
+
+//added pragma version
+ pragma solidity ^0.4.0;
+ 
+ contract TimeLock {
+
+     mapping(address => uint) public balances;
+     mapping(address => uint) public lockTime;
+
+     function deposit() public payable {
+         balances[msg.sender] += msg.value;
+         lockTime[msg.sender] = now + 1 weeks;
+     }
+
+     function increaseLockTime(uint _secondsToIncrease) public {
+         // <yes> <report> ARITHMETIC
+         lockTime[msg.sender] += _secondsToIncrease;
+     }
+
+     function withdraw() public {
+         require(balances[msg.sender] > 0);
+         require(now > lockTime[msg.sender]);
+         uint transferValue = balances[msg.sender];
+         balances[msg.sender] = 0;
+         msg.sender.transfer(transferValue);
+     }
+ }