Fix oz usage

Also add documentation for compiling with library contracts.

Author: konradkonrad

.gitignore

@@ -1,2 +1,3 @@
 config.json
-private_config.json
+private_config.json
+./solc_out

README.md

@@ -109,7 +109,16 @@ If your wallet is not connected to **Gnosis Chain**, the app will prompt you to
   - `commitPrediction(bytes _encryptedData, uint256 _revealTime, string _shutterIdentity)`
   - `revealPrediction(uint256 _id, string _plaintext)`
 
+### **Compiling**
 
+```
+solc \
+    --output-dir=./solc_out/ \
+    --base-path=./contracts \
+    --include-path=lib \
+    --combined-json=abi,bin,bin-runtime \
+    contracts/PredictionContract.sol
+```
 
 ## **Development**
 

contracts/PredictionContract.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
-import "@openzeppelin/contracts/ownership/Ownable.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
 
 /**
  * @title PredictionContract
@@ -35,7 +35,7 @@ contract PredictionContract is Ownable {
         string revealedText
     );
 
-    constructor(uint256 _commitmentFee) {
+    constructor(uint256 _commitmentFee) Ownable(msg.sender) {
         commitmentFee = _commitmentFee;
     }
 
@@ -124,7 +124,7 @@ contract PredictionContract is Ownable {
      * @dev Allows the owner to withdraw collected fees.
      */
     function withdrawFees() external onlyOwner {
-        payable(owner).transfer(address(this).balance);
+        payable(msg.sender).transfer(address(this).balance);
     }
 
     /**