Added a quick setup guide for developers

Documentation-develop/SETUP.md

+QFQ Development Setup
+=================
+
+Requirements
+============
+
+ * Node.js
+ * PHP7.x - for local testing
+ * Python
+ * IDE (Used: PhpStorm, VSCode)
+
+Mac OS X
+--------
+To be able to install various unix tools that are used, it is recommended to install homebrew from https://brew.sh
+
+Afterwards use:
+```brew install php@7.2 wget```
+
+VSCode
+------
+
+It is recommended to install the standard PHP, Python and Javascript plugins (Can be selected at the start). 
+
+Additional useful Extensions: 
+ * `Tasks Panel` - allows you to start Grunt Tasks.
+ * `Beautify` - Opinionated Javascript Code beautifier.
+ * `JSLint` - Javascript Linting for old Ecma Script.
+ * `PHP Debug` - Support for PHP XDebug
+ * `PHP IntelliSense` - Advanced Autocompletion and Refactoring for PHP
+ * `PHP Intelephense` - Similar features to PHPStorm (has additional premium functionality)
+
+Preparations
+------------
+
+You can use the command `make bootstrap` from the root folder of the git QFQ project to setup your Development Enviroment.
+
+To only set it up for running mock ups, use:
+```
+sudo npm install grunt-cli -g
+npm update
+grunt default
+```
+from the root directory of the git QFQ project.
+
+Working with Mockups
+--------------------
+Mockups are in the `mockup` directory.
+
+To access them, you need a locally running webserver. The easiest way is to use the local webserver provided by php. 
+
+`php -S localhost:8000`
+
+Now you can access the mockups by going to http://localhost:8000/mockup/qfqform.html 
+