doc: Added contributing.md (#826)

Author: JohnstonCode

.vscodeignore

@@ -20,4 +20,5 @@ test/**
 tsconfig.json
 tslint.json
 vsc-extension-quickstart.md
-.dependabot/**
+.dependabot/**
+images/docs/**

CONTRIBUTING.md

@@ -0,0 +1,49 @@
+# Contributing
+
+Before you contribute to this project, please open an issue beforehand to discuss the changes you want to make.
+
+## Development setup
+
+Requirements    
+* [Git](https://git-scm.com/)
+* [NodeJs](https://nodejs.org/) >= 12.4.0
+* [yarn](https://classic.yarnpkg.com/lang/en/) >= 1.22
+
+First you will need to fork the project
+![Github Fork](images/docs/fork.png)
+
+Then clone your fork
+```
+git clone https://github.com/<YOUR_USERNAME>/svn-scm.git
+```
+
+### Dependencies
+To install all of the required dependencies run
+```
+yarn --frozen-lockfile
+```
+
+### Build
+To build the extension
+```
+yarn run build
+```
+
+### Watch
+For development run in watch mode
+```
+yarn run compile
+```
+
+### Formatting
+This project uses [prettier](https://prettier.io/) for code formatting. You can run prettier across the code by calling `yarn run style-fix`
+
+### Linting
+This project uses [ESLint](https://eslint.org/) for code linting. You can run ESLint across the code by calling `yarn run lint`. To fix fixable errors run `yarn run lint:fix`
+
+### Debugging
+Run in VS Code
+1. Open the `svn-scm` folder
+2. Make sure the [dependencies](#dependencies) are installed
+3. Run in [watch](#watch) mode
+4. Choose the `Launch Extension` launch configuration from the launch dropdown in the Debug viewlet and press `F5`.