Added Contribute section to the readme and wiki.

Author: Visser

README.md

@@ -23,4 +23,8 @@ Want custom [keybindings](https://github.com/Dickurt/vscode-php-formatter/wiki/C
 
 ## Troubleshooting
 
-Set up the extension, but can't get it to work? Check the [Troubleshooting](https://github.com/Dickurt/vscode-php-formatter/wiki/Troubleshooting) section.
+Set up the extension, but can't get it to work? Check the [Troubleshooting](https://github.com/Dickurt/vscode-php-formatter/wiki/Troubleshooting) section.
+
+## Contribute
+
+Want to add a feature or fix an error? Follow the [Contribute](https://github.com/Dickurt/vscode-php-formatter/wiki/Contribute) section on the wiki to get started.

wiki/Contribute.md

@@ -0,0 +1,10 @@
+Want to add a feature or fix an error? You've come to the right place!
+
+**Getting started**
+
+1. Clone the project to your system's VSCode extension folder.
+2. Open a terminal in the cloned folder.
+3. Run `npm install`
+4. Run `npm postinstall`
+5. Run `npm run-script build` to build your code, or run `npm run-script watch` to automatically build when a file changes.
+6. **Done!**