add default delegation

contracts/democracy/DefaultDelegation.sol

@@ -0,0 +1,59 @@
+pragma solidity >=0.5.0 <0.6.0;
+
+import "./Delegation.sol";
+import "../common/Controlled.sol";
+
+contract DefaultDelegation is Delegation, Controlled {
+    address public defaultDelegate;
+    
+    constructor(address _defaultDelegate) public {
+        defaultDelegate = _defaultDelegate;
+    }
+
+    /** 
+     * @notice Changes default delegation
+     * @param _to What is the default delegate.
+     */
+    function delegate(address _to) external onlyController {
+        defaultDelegate = _to;
+    }
+
+    function delegatedTo(address)
+        external
+        view 
+        returns (address directDelegate) 
+    {
+        return defaultDelegate;
+    }
+    
+    function delegationOf(address)
+        external
+        view
+        returns(address finalDelegate) 
+    {
+        return defaultDelegate;
+    }
+
+    function delegatedToAt(
+        address,
+        uint
+    )
+        external
+        view
+        returns (address directDelegate) 
+    {
+        return defaultDelegate;
+    }
+    
+    function delegationOfAt(
+        address,
+        uint
+    )
+        external
+        view
+        returns(address finalDelegate) 
+    {
+        return defaultDelegate;
+    }
+    
+}

contracts/democracy/Democracy.sol

@@ -2,6 +2,7 @@ pragma solidity >=0.5.0 <0.6.0;
 
 import "../token/MiniMeToken.sol";
 import "./DelegationFactory.sol";
+import "./DefaultDelegation.sol";
 import "./TrustNetwork.sol";
 import "./ProposalCuration.sol";
 import "./ProposalManager.sol";
@@ -23,7 +24,7 @@ contract Democracy {
 
     constructor(MiniMeToken _token, DelegationFactory _DelegationFactory) public {
         token = _token;
-        trustNet = new TrustNetwork(_DelegationFactory);
+        trustNet = new TrustNetwork(_DelegationFactory, new DefaultDelegation());
         proposalManager = new ProposalCuration(_token, trustNet).proposalManager();
     }
 

contracts/democracy/TrustNetwork.sol

@@ -21,9 +21,9 @@ contract TrustNetwork is TrustNetworkInterface, Controlled {
         Delegation vetoDelegation;
     }
     
-    constructor(DelegationFactory _delegationFactory) public {
+    constructor(DelegationFactory _delegationFactory, Delegation defaultDelegation) public {
         delegationFactory = _delegationFactory;
-        topics[bytes32(0)] = newTopic(address(0), address(0));
+        topics[bytes32(0)] = newTopic(defaultDelegation, defaultDelegation);
     }
     
     function addTopic(bytes32 topicId, bytes32 parentTopic) public onlyController {
@@ -67,10 +67,10 @@ contract TrustNetwork is TrustNetworkInterface, Controlled {
     }
 
     
-    function newTopic(address _vote, address _veto) internal returns (Topic memory topic) {
+    function newTopic(Delegation _vote, Delegation _veto) internal returns (Topic memory topic) {
         topic = Topic ({ 
-            voteDelegation: Delegation(address(delegationFactory.createDelegation(_vote))),
-            vetoDelegation: Delegation(address(delegationFactory.createDelegation(_veto)))
+            voteDelegation: Delegation(address(delegationFactory.createDelegation(address(_vote)))),
+            vetoDelegation: Delegation(address(delegationFactory.createDelegation(address(_vote))))
         });
     }