convert MintedCrowdsale to initializers

contracts/crowdsale/emission/MintedCrowdsale.sol

 pragma solidity ^0.4.24;
 
+import "../../Initializable.sol";
 import "../Crowdsale.sol";
 import "../../token/ERC20/ERC20Mintable.sol";
 
@@ -9,7 +10,7 @@ import "../../token/ERC20/ERC20Mintable.sol";
  * @dev Extension of Crowdsale contract whose tokens are minted in each purchase.
  * Token ownership should be transferred to MintedCrowdsale for minting.
  */
-contract MintedCrowdsale is Crowdsale {
+contract MintedCrowdsale is Initializable, Crowdsale {
 
   /**
    * @dev Overrides delivery by minting tokens upon purchase.

contracts/mocks/MintedCrowdsaleImpl.sol

 pragma solidity ^0.4.24;
 
+import "../Initializable.sol";
 import "../token/ERC20/ERC20Mintable.sol";
 import "../crowdsale/emission/MintedCrowdsale.sol";
 
 
-contract MintedCrowdsaleImpl is MintedCrowdsale {
+contract MintedCrowdsaleImpl is Initializable, MintedCrowdsale {
 
   constructor (
     uint256 rate,
@@ -14,6 +15,7 @@ contract MintedCrowdsaleImpl is MintedCrowdsale {
     public
     Crowdsale(rate, wallet, token)
   {
+    Crowdsale.initialize(rate, wallet, token);
   }
 
 }

test/crowdsale/MintedCrowdsale.test.js

@@ -5,7 +5,7 @@ const { assertRevert } = require('../helpers/assertRevert');
 const BigNumber = web3.BigNumber;
 
 const MintedCrowdsale = artifacts.require('MintedCrowdsaleImpl');
-const ERC20Mintable = artifacts.require('ERC20Mintable');
+const ERC20Mintable = artifacts.require('ERC20MintableMock');
 const ERC20 = artifacts.require('ERC20');
 
 contract('MintedCrowdsale', function ([_, deployer, investor, wallet, purchaser]) {