convert Pausable to initializers

contracts/lifecycle/Pausable.sol

 pragma solidity ^0.4.24;
 
+import "../Initializable.sol";
 import "../access/roles/PauserRole.sol";
 
 
@@ -7,12 +8,15 @@ import "../access/roles/PauserRole.sol";
  * @title Pausable
  * @dev Base contract which allows children to implement an emergency stop mechanism.
  */
-contract Pausable is PauserRole {
+contract Pausable is Initializable, PauserRole {
   event Paused();
   event Unpaused();
 
   bool private _paused = false;
 
+  function initialize() public initializer {
+    PauserRole.initialize();
+  }
 
   /**
    * @return true if the contract is paused, false otherwise.

contracts/mocks/PausableMock.sol

 pragma solidity ^0.4.24;
 
 
+import "../Initializable.sol";
 import "../lifecycle/Pausable.sol";
 import "./PauserRoleMock.sol";
 
 
 // mock class using Pausable
-contract PausableMock is Pausable, PauserRoleMock {
+contract PausableMock is Initializable, Pausable, PauserRoleMock {
   bool public drasticMeasureTaken;
   uint256 public count;
 
   constructor() public {
+    Pausable.initialize();
+
     drasticMeasureTaken = false;
     count = 0;
   }