styling in Migrations.sol

contracts/Migrations.sol

@@ -1,23 +1,21 @@
 pragma solidity ^0.4.21;
 
-contract Migrations {
-  address public owner;
-  uint public last_completed_migration;
+import "zeppelin-solidity/contracts/ownership/Ownable.sol";
 
-  modifier restricted() {
-    if (msg.sender == owner) _;
-  }
+// This is a truffle contract, needed for truffle integration.
+contract Migrations is Ownable {
+    uint256 public lastCompletedMigration;
 
-  function Migrations() public {
-    owner = msg.sender;
-  }
+    function Migrations() public {
+        owner = msg.sender;
+    }
 
-  function setCompleted(uint completed) public restricted {
-    last_completed_migration = completed;
-  }
+    function setCompleted(uint _completed) public onlyOwner {
+        lastCompletedMigration = _completed;
+    }
 
-  function upgrade(address new_address) public restricted {
-    Migrations upgraded = Migrations(new_address);
-    upgraded.setCompleted(last_completed_migration);
-  }
+    function upgrade(address _newAddress) public onlyOwner {
+        Migrations upgraded = Migrations(_newAddress);
+        upgraded.setCompleted(lastCompletedMigration);
+    }
 }