Ownership transaction predicate

packages/contracts/.solhint.json

@@ -0,0 +1,3 @@
+{
+  "extends": "solhint:default"
+}

packages/contracts/contracts/BasicTokenMock.sol

@@ -5,7 +5,7 @@ import "openzeppelin-solidity/contracts/token/ERC20/ERC20.sol";
 
 // Example class - a mock class using delivering from ERC20
 contract BasicTokenMock is ERC20 {
-  constructor(address initialAccount, uint256 initialBalance) public {
-    super._mint(initialAccount, initialBalance);
-  }
+    constructor(address initialAccount, uint256 initialBalance) public {
+        super._mint(initialAccount, initialBalance);
+    }
 }

packages/contracts/contracts/CommitmentChain.sol

@@ -0,0 +1,12 @@
+pragma solidity ^0.5.0;
+pragma experimental ABIEncoderV2;
+
+/* Internal Imports */
+import {DataTypes as dt} from "./DataTypes.sol";
+
+contract CommitmentChain {
+    function verifyInclusion(dt.StateUpdate memory _stateUpdate, bytes memory _inclusionProof) public returns (bool) {
+        // Always return true for now until we can verify inclusion proofs.
+        return true;
+    }
+}

packages/contracts/contracts/DataTypes.sol

@@ -0,0 +1,39 @@
+pragma solidity ^0.5.0;
+pragma experimental ABIEncoderV2;
+
+/**
+ * @title DataTypes
+ * @notice TODO
+ */
+contract DataTypes {
+
+    /*** Structs ***/
+    struct Range {
+        uint256 start;
+        uint256 end;
+    }
+
+    struct StateObject {
+        address predicateAddress;
+        bytes data;
+    }
+
+    struct StateUpdate {
+        StateObject stateObject;
+        Range range;
+        uint256 plasmaBlockNumber;
+        address depositAddress;
+    }
+
+    struct Checkpoint {
+        StateUpdate stateUpdate;
+        Range subrange;
+    }
+
+    struct Transaction {
+        address depositAddress;
+        bytes32 methodId;
+        bytes parameters;
+        Range range;
+    }
+}