added examples

contracts/examples/SampleTokenVesting.sol

@@ -0,0 +1,23 @@
+pragma solidity ^0.4.24;
+
+import "../drafts/TokenVesting.sol";
+
+/**
+ * @title SampleTokenVesting
+ * @dev This is an example of a token vesting for defined time period. 
+ * Tokens to be vested will be sent directly to this contract.
+ */
+
+contract SampleTokenVesting is TokenVesting{
+
+    constructor(
+        address beneficiary, 
+        uint256 start, 
+        uint256 cliffDuration, 
+        uint256 duration, 
+        bool revocable
+    ) 
+    public
+    TokenVesting(beneficiary, start, cliffDuration, duration, revocable){}
+
+}