📚 Improve documentation about how to contribute to n8n

CONTRIBUTING.md

@@ -0,0 +1,107 @@
+# Contributing to n8n
+
+Great that you are here and you want to contribute to n8n
+
+
+## Code of Conduct
+
+This project and everyone participating in it are governed by the Code of
+Conduct which can be found in the file [CODE_OF_CONDUCT.md](CODE_OF_CONDUCT.md).
+By participating, you are expected to uphold this code. Please report
+unacceptable behavior to jan@n8n.io.
+
+
+## Directory Structure
+
+n8n is split up in different modules which are all in a single mono repository.
+
+The most important directories:
+
+ - [/docker/image](/docker/image) - Dockerfiles to create n8n containers
+ - [/docker/compose](/docker/compose) - Examples Docker Setups
+ - [/packages](/packages) - The different n8n modules
+ - [/packages/cli](/packages/cli) - CLI code to run front- & backend
+ - [/packages/core](/packages/core) - Core code which handles workflow
+                                      execution, active webhooks and
+                                      workflows
+ - [/packages/editor-ui](/packages/editor-ui) - Vue frontend workflow editor
+ - [/packages/node-dev](/packages/node-dev) - Simple CLI to create new n8n-nodes
+ - [/packages/nodes-base](/packages/nodes-base) - Base n8n nodes
+ - [/packages/worflow](/packages/worflow) - Workflow code with interfaces which
+                                            get used by front- & backend
+
+
+## Development Setup
+
+If you want to change or extend n8n you have to make sure that all needed
+dependencies are installed and the packages get linked correctly. Here a short guide on how that can be done:
+
+
+### Requirements
+
+
+#### Build Tools
+
+That all the packages which n8n uses can be installed and compiled correctly
+the essential build tools must be installed. This is probably already the case
+for the most people but if you are totally new to development or just setting
+up a new computer it is probably still missing.
+
+Linux:
+```
+apt-get install -y build-essential python
+```
+
+Windows:
+```
+npm install -g windows-build-tools
+```
+
+#### lerna
+
+n8n is split up in different modules which are all in a single mono repository.
+To make development as easy as possible does [lerna](https://lerna.js.org) get
+used. It automatically sets up file-links between modules which depend on each
+other.
+
+So for the setup to work correctly lerna has to be installed globally like this:
+
+```
+npm install -g lerna
+```
+
+
+### Actual n8n setup
+
+Now that everything n8n requires to run is installed the actual n8n code can be
+checked out and set up:
+
+1. Clone the repository
+	```
+	git clone https://github.com/n8n-io/n8n.git
+	```
+
+2. Go into repository folder
+	```
+	cd n8n
+	```
+
+3. Install all dependencies of all modules and link them together:
+	```
+	lerna bootstrap --hoist
+	```
+
+4. Build all the code:
+	```
+	npm run build
+	```
+
+
+
+### Start
+
+To start n8n execute:
+
+```
+npm run start
+```

README.md

@@ -33,11 +33,7 @@ And information about how to run it in Docker [here](https://github.com/n8n-io/n
 
 ## Development Setup
 
-1. Clone the repository
+A guide how to set everything up can be found in the file [CONTRIBUTING.md](CONTRIBUTING.md)
-2. Go into repository folder
-3. Run: `npm install`
-4. Run: `npx lerna bootstrap --hoist`
-5. Run: `npm run build` or `npx lerna exec npm run build` (if lerna is not installed)