Add Installation chapter

README.md

@@ -6,4 +6,34 @@
 ![Docker Image Version (latest semver)](https://img.shields.io/docker/v/wernerfred/docker-rainloop?label=Latest%20Image)
 ![GitHub Release Date](https://img.shields.io/github/release-date/wernerfred/docker-rainloop?label=Release%20Date)
 
-# docker-rainloop
+# Host your own rainloop instance using docker
+
+This project allows you to host your own instance of [rainloop ](https://github.com/RainLoop/rainloop-webmail) (licensed under [GNU AGPL v3](https://choosealicense.com/licenses/agpl-3.0/)) using docker.
+
+## Installation
+
+### Build from source
+
+To build this project from source make sure to clone the repository from github and change your working directroy into that newly created directory. Then simly issue the ```docker build``` like shown:
+
+```
+docker build -t wernerfred/docker-rainloop .
+```
+
+### Pull from DockerHub
+
+Another possibility is pulling the image directly from the [DockerHub repository](https://hub.docker.com/r/wernerfred/rainloop). Every release on this project automatically triggers a new build based on the master branch.
+
+```
+docker pull wernerfred/docker-rianloop
+``` 
+
+### Run container
+
+To run the container user ```docker run```. You might adjust the following command according to your neeeds:
+
+```
+docker run -d \
+           -p 80:80 \
+           wernerfred/docker-rainloop
+```