first commit

contracts/lib/Ownable.sol

@@ -0,0 +1,43 @@
+/*
+
+    Copyright 2020 DODO ZOO.
+    SPDX-License-Identifier: Apache-2.0
+
+*/
+
+pragma solidity 0.6.9;
+pragma experimental ABIEncoderV2;
+
+/**
+ * @title Ownable
+ * @author DODO Breeder
+ *
+ * @notice Ownership related functions
+ */
+contract Ownable {
+    address public _OWNER_;
+
+    // ============ Events ============
+
+    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
+
+    // ============ Modifiers ============
+
+    modifier onlyOwner() {
+        require(msg.sender == _OWNER_, "NOT_OWNER");
+        _;
+    }
+
+    // ============ Functions ============
+
+    constructor() internal {
+        _OWNER_ = msg.sender;
+        emit OwnershipTransferred(address(0), _OWNER_);
+    }
+
+    function transferOwnership(address newOwner) external onlyOwner {
+        require(newOwner != address(0), "INVALID_OWNER");
+        emit OwnershipTransferred(_OWNER_, newOwner);
+        _OWNER_ = newOwner;
+    }
+}