add makefile

Makefile

@@ -0,0 +1,20 @@
+.PHONY: main keys_en-us-intl keys_de help
+
+.DEFAULT_GOAL := help
+
+main:  ## generate main case
+	# TODO: split into printable pieces
+	openscad --export-format binstl -o main.stl main.scad
+	openscad -o main.3mf main.scad
+
+keys_en-us-intl:  ## generate key caps with english us interational layout
+	openscad --export-format binstl -o keys_en-us-intl.stl keys_en-us-intl.scad
+	openscad -o keys_en-us-intl.3mf keys_en-us-intl.scad
+
+keys_de:  ## generate key caps with german layout
+	openscad --export-format binstl -o keys_de.stl keys_de.scad
+	openscad -o keys_de.3mf keys_de.scad
+
+help:  ## display this help
+	@fgrep -h "##" $(MAKEFILE_LIST) | fgrep -v fgrep | sed -e 's/\\$$//' | sed -e 's/##//'
+

README.md

@@ -11,14 +11,18 @@ Follow the guide at https://mkbd65.xengi.de to build a case for your phone.
 
 _TBA_
 
+```shell
+make main
+```
+
 ## Generate a key set
 
 To generate the key set you can either use a predefined layout or generate your own. There are two predefined layouts
 for English US International and German. You can generate the 3D files for them with the following commands:
 
 ```shell
-make keys:en-us-intl
-make keys:de
+make keys_en-us-intl
+make keys_de
 ```
 
 This will generate the neccessary 3MF and STL files that you can use for your 3D printers slicer software. I recommend a