WorkHistory smart contract

WorkHistory.sol

contract WorkHistory {
    event TaskProof(string taskProof, int amount, address authorizer, address to);
    mapping(string => bool) taskProofExists;
    
    /*  taskProof is a unique id such as an IPFS hash 
        amount is the amount granted to the _to address by the _authorizer
    */
    function register(string _taskProof, int amount, address _authorizer, address _to) returns(bool success) {
        if(taskProofExists[_taskProof]) {
            return false;
        } else {
            TaskProof(_taskProof, amount, _authorizer, _to);
            taskProofExists[_taskProof] = true;
            return true;
        }
    }
}