Let's do some docs

Author: uded

README.md

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+# Java Docker health check app
+
+Docker, since verions 1.12 or so, have a neat feature to run a health check on a container. 
+
+#### Great! Let's do it with `curl` or `iwr`
+Healt check is a really simple thing to implement. You call a service, and it should `0` if it works and `1` if it does
+not. Simple? Sure, even Docker dockumentation will tell you how to do it with HTTP based service using `curl`:
+
+```
+HEALTHCHECK --interval=5m --timeout=3s \
+  CMD curl -f http://localhost/ || exit 1
+```
+
+Here, every 5 minutes with a timeout of 3 seconds `localhost` will be called. Using `curl`. On Windows, using IWR, it's
+a bit more complicate, but still - it works. It's simple in the end. Right? 
+
+So why this lib?
+
+#### The problem with `curl` and `iwr`
+1. In Linux images, you need to have curl installed. You can start `FROM` alpine and have a 4MB base image. But guess 
+what - it doesn't come with `curl` pre-installed. So you need to add `RUN apk --update --no-cache add curl`. Sure, 
+no sweat, easy to do. That will add a new layer of 2.5MB to the image. And additional headaches of curl and libraries. 
+2. In Windows images, you need to have PowerShell installed. But recent Nano images will not have it. To save space. 
+Makes sense, right?
+3. If you choose any of the above you loose portability. Different scripts for health-checks depending on the platform. 
+Sure, no biggie... but what for? You have Java installed already. You had to install it. Or find an image that have Java
+since your app will rely on it. Right? Let's use it...
+
+### Here comes the solution
+A simple library. <100kb. You run it as a Java command line app. Yes, it has to start up Java... but that is not really 
+a huge deal nowadays.