add gov v3

contracts/v2-vault-and-gas/ProposalChanges.md

@@ -1,5 +1,7 @@
 # Tornado Governance Changes
 
+Governance proposal [repo]().
+
 ## Governance Vault Upgrade (GovernanceVaultUpgrade.sol)
 
 `GovernanceVaultUpgrade` is the first major upgrade to tornado governance. This upgrade introduces new logic which is used to communicate with `TornVault` from the governance contract. The motivation behind this upgrade:

contracts/v3-relayer-registry/GovernanceStakingUpgrade.sol

@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.6.12;
+pragma experimental ABIEncoderV2;
+
+import { GovernanceGasUpgrade } from "../v2-vault-and-gas/GovernanceGasUpgrade.sol";
+import { ITornadoStakingRewards } from "./interfaces/ITornadoStakingRewards.sol";
+
+/**
+ * @notice The Governance staking upgrade. Adds modifier to any un/lock operation to update rewards
+ * @dev CONTRACT RISKS:
+ *      - if updateRewards reverts (should not happen due to try/catch) locks/unlocks could be blocked
+ *      - generally inherits risks from former governance upgrades
+ */
+contract GovernanceStakingUpgrade is GovernanceGasUpgrade {
+  ITornadoStakingRewards public immutable Staking;
+
+  event RewardUpdateSuccessful(address indexed account);
+  event RewardUpdateFailed(address indexed account, bytes indexed errorData);
+
+  constructor(
+    address stakingRewardsAddress,
+    address gasCompLogic,
+    address userVaultAddress
+  ) public GovernanceGasUpgrade(gasCompLogic, userVaultAddress) {
+    Staking = ITornadoStakingRewards(stakingRewardsAddress);
+  }
+
+  /**
+   * @notice This modifier should make a call to Staking to update the rewards for account without impacting logic on revert
+   * @dev try / catch block to handle reverts
+   * @param account Account to update rewards for.
+   * */
+  modifier updateRewards(address account) {
+    try Staking.updateRewardsOnLockedBalanceChange(account, lockedBalance[account]) {
+      emit RewardUpdateSuccessful(account);
+    } catch (bytes memory errorData) {
+      emit RewardUpdateFailed(account, errorData);
+    }
+    _;
+  }
+
+  function lock(
+    address owner,
+    uint256 amount,
+    uint256 deadline,
+    uint8 v,
+    bytes32 r,
+    bytes32 s
+  ) public virtual override updateRewards(owner) {
+    super.lock(owner, amount, deadline, v, r, s);
+  }
+
+  function lockWithApproval(uint256 amount) public virtual override updateRewards(msg.sender) {
+    super.lockWithApproval(amount);
+  }
+
+  function unlock(uint256 amount) public virtual override updateRewards(msg.sender) {
+    super.unlock(amount);
+  }
+}

contracts/v3-relayer-registry/ProposalChanges.md

@@ -0,0 +1,14 @@
+# Tornado Relayer Registry
+
+Governance proposal [repo](https://github.com/Rezan-vm/tornado-relayer-registry).
+
+Governance upgrade which includes a registry for relayer registration and staking mechanisms for the TORN token.
+
+## Overview
+
+1. Anyone can become a relayer by staking TORN into Registry contract.
+2. Minimum stake is governed by the Governance.
+3. Each Pool has its own fee % which is also set by the Governance.
+4. On every withdrawal via relayer, the relayer has to pay the Tornado Pool fee in TORN. The fee is deducted from his staked balance.
+5. All collected fees are stored into StakingReward contract.
+6. Any TORN holder can stake their TORN into Governance contract like they were before, but earning fees proportionately to their stake.

contracts/v3-relayer-registry/interfaces/ITornadoStakingRewards.sol

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+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.6.12;
+
+interface ITornadoStakingRewards {
+  function updateRewardsOnLockedBalanceChange(address account, uint256 amountLockedBeforehand) external;
+}