Election.sol needs to be updated for solidity ^0.5.8

[urwa]

Hi,

I was using Election.sol and could not compile it. With the solidity version ^0.5.8, the following changes are required.

SUMMARY:

• update solidity version.
• error message for require().
• public before other modifiers.
• valid argument in selfdestruct().

DETAILS:

• pragma solidity ^0.4.21; to be changed to pragma solidity ^0.5.8;

• require(msg.sender == owner); to be changed to require(msg.sender == owner, "Sender NOT authorized.");

• constructor(string _name) public {...} to be changed to constructor(string memory _name) public {...}

• function addCandidate(string name) ownerOnly public {...} to be changed to function addCandidate(string memory name) public ownerOnly {...}

• function authorize(address person) ownerOnly public {...} to be changed to function authorize(address person) public ownerOnly {...}

• require(!voters[msg.sender].voted); to be changed to require(!voters[msg.sender].voted, "Voter has already voted");

• require(voters[msg.sender].authorized); to be changed to require(voters[msg.sender].authorized, "Voter not authorized");

• function end() ownerOnly public {...} to be changed to function end() public ownerOnly {...}

• selfdestruct(owner); to be changed to selfdestruct(msg.sender);

I am not sure if this workshop contracts requires updating but searching Election.sol by Blockgeeks gives this as a top search result. And I think new people can benefit from this.