Add basic configuration and image into readme

Author: jraska

README.md

@@ -2,3 +2,15 @@
 Gradle plugin to keep your modules graph healthy and lean.
 
 [![CircleCI](https://circleci.com/gh/jraska/modules-graph-assert.svg?style=svg)](https://circleci.com/gh/jraska/modules-graph-assert)
+
+## Assert your modules graph
+<img width="1281" alt="example_graph" src="https://user-images.githubusercontent.com/6277721/70832705-18980e00-1df6-11ea-8b78-fc07ba570a2b.png">
+
+## Configuration
+```groovy
+moduleGraphAssert {
+  maxHeight = 4
+  moduleLayersFromTheTop = [":feature", ":lib", ":core"]
+  restrinctInLayerDependencies = [":feature", ":lib"]
+}
+```