Add SB Curated (copied from the smartbugs repository).

dataset/arithmetic/token.sol

@@ -0,0 +1,30 @@
+/*
+ * @source: https://github.com/sigp/solidity-security-blog
+ * @author: Steve Marx
+ * @vulnerable_at_lines: 20,22
+ */
+
+ pragma solidity ^0.4.18;
+
+ contract Token {
+
+   mapping(address => uint) balances;
+   uint public totalSupply;
+
+   function Token(uint _initialSupply) {
+     balances[msg.sender] = totalSupply = _initialSupply;
+   }
+
+   function transfer(address _to, uint _value) public returns (bool) {
+     // <yes> <report> ARITHMETIC
+     require(balances[msg.sender] - _value >= 0);
+     // <yes> <report> ARITHMETIC
+     balances[msg.sender] -= _value;
+     balances[_to] += _value;
+     return true;
+   }
+
+   function balanceOf(address _owner) public constant returns (uint balance) {
+     return balances[_owner];
+   }
+ }