1pragma solidity ^0.6.0;
 2
 3contract Migrations {
 4  address public owner;
 5  uint public last_completed_migration;
 6
 7  constructor() public {
 8    owner = msg.sender;
 9  }
10
11  modifier restricted() {
12    if (msg.sender == owner) _;
13  }
14
15  function setCompleted(uint completed) public restricted {
16    last_completed_migration = completed;
17  }
18
19  function upgrade(address new_address) public restricted {
20    Migrations upgraded = Migrations(new_address);
21    upgraded.setCompleted(last_completed_migration);
22  }
23}