Write 'Repository overview' for README

Providing a structural overview inside the README should help developers
new to the repository to get familiar with it.

1 files changed, 35 insertions, 0 deletions

diff --git a/README.md b/README.md
index 5703698..cdfcabe 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,38 @@
 # soundbox
 
 soundbox is a device to connect classic audio systems to the network.
+
+## Repository overview
+
+The following listing provides an overview of the repository structure:
+
+```
+.
+├── build
+├── doc
+│   ├── LICENSE.txt
+│   └── soundbox-documentation.tex
+├── Makefile
+├── mech
+│   ├── assembly.scad
+│   ├── LICENSE.txt
+│   ├── parameters.scad
+│   ├── pcb_case
+│   │   └── tolerance_tests.scad
+│   ├── production.scad
+│   └── prusa-slicer
+│       └── anycubic_i3_mega_s.ini
+└── README.md
+```
+
+The repository root contains the given `README`, a Makefile which allows to
+build everything with GNU make, the build folder and further folders for
+different aspects of the device.
+
+The `doc` folder contains everything to build the PDF documentation which is
+generated during a full build. It contains all documentation aspects except the
+content covered in the given `README`.
+
+Mechanical design is handled inside the `mech` directory. It consists of source
+files for OpenSCAD aswell as configuration file(s) for the Prusa Slicer
+software.