Adding interface to reverse registrar

contracts/IReverseRegistrar.sol

@@ -0,0 +1,10 @@
+pragma solidity >=0.4.24;
+
+interface IReverseRegistrar {
+
+    function claim(address owner) external returns (bytes32);
+    function claimWithResolver(address owner, address resolver) external returns (bytes32);
+    function setName(string calldata name) external returns (bytes32);
+    function node(address addr) external pure returns (bytes32);
+
+}

contracts/ReverseRegistrar.sol

@@ -1,12 +1,13 @@
 pragma solidity ^0.5.0;
 
 import "./ENS.sol";
+import "./IReverseRegistrar.sol";
 
 contract Resolver {
     function setName(bytes32 node, string memory name) public;
 }
 
-contract ReverseRegistrar {
+contract ReverseRegistrar is IReverseRegistrar{
     // namehash('addr.reverse')
     bytes32 public constant ADDR_REVERSE_NODE = 0x91d1777781884d03a6757a803996e38de2a42967fb37eeaca72729271025a9e2;
 
@@ -28,7 +29,7 @@ contract ReverseRegistrar {
             oldRegistrar.claim(msg.sender);
         }
     }
-    
+
     /**
      * @dev Transfers ownership of the reverse ENS record associated with the
      *      calling account.