docs: add documentation

.gitignore

@@ -0,0 +1 @@
+.idea

README.md

@@ -1,5 +1,51 @@
-# baseimage alpine
-[![Build Status](https://drone.jcg.re/api/badges/jcgruenhage/docker-baseimage-alpine/status.svg)](https://drone.jcg.re/jcgruenhage/docker-baseimage-alpine)
+# docker.jcg.re/base-alpine
+[![Build Status](https://drone.jcg.re/api/badges/jcgruenhage/docker-base-alpine/status.svg)](https://drone.jcg.re/jcgruenhage/docker-base-alpine)
 
-A little baseimage based on alpine and s6. Docs coming soon :tm:
+A small base image based on [Alpine Linux](https://www.alpinelinux.org/) (current stable release) and 
+[s6](http://www.skarnet.org/software/s6/index.html).
 
+### Building on top of this
+
+To build on top of this image, you can base a Dockerfile on this:
+
+```dockerfile
+FROM docker.jcg.re/base-alpine
+MAINTAINER Your Name <your@email.adress>
+
+RUN echo "install stuff here"
+
+ADD root /
+```
+
+The folder structure of root should look kinda like this, every of these parts is optional:
+```
+root
+|-- etc
+|   |-- s6
+|   |   |-- your-service
+|   |   |   |-- run
+|   |   |   |-- finish
+|   |   |   |-- crash
+|   |-- periodic
+|   |   |-- hourly
+|   |   |   |-- somescript
+```
+The folder your-service should contain three executables:
+ - `run`, is run when the service is started (container startup)
+ - `finish`, is run when the service is stopped
+ - `crash`, is run when the service crashes
+
+Also, your-service is an example name, you should replace it with the name of the software running in there.
+
+
+Inside the `/etc/periodic` folder, there are 5 folders:
+ - 15min
+ - hourly
+ - daily
+ - weekly
+ - monthly
+
+Inside those, you can put executable shell scripts (starting with `#!/bin/sh`), 
+and they'll be executed regularly in the specified interval. 
+
+For custom intervals, you can always edit crontab.