readme: added basic project information

* about usage
* about building
* about ready to use binaries

README.md

@@ -3,3 +3,54 @@
 
 ![qr](docs/logo_qr.svg)
 
+## Usage
+This software currently supports outputting to the following formats:
+
+* svg
+* PNG
+* JPG
+* Bitmap
+
+or directly to the console, as kind of an *"ascii art"*.  
+after installing via `make install`, you can read more in the man page by calling `man qr`.
+### Options
+```
+  -f --format     output file format. can be one of "cli, png, svg, jpg, bmp"
+  -h --help       show this help
+  -i --input      take data from this argument instead of stdin
+  -o --output     output file name without extension
+  -s --size       desired output file size in pixels
+  -t --type       output QR code type. can be one of "small, medium, large"
+  -v --version    shows version info
+```
+
+### Examples
+```bash
+bash> qr -i "this is from parameter" -f png -s 512 -o my_qrcode_file
+
+bash> echo "this is from stdin" | qr -t small -f png -s 512 -o my_qrcode_file_with_low_ecc
+```
+
+## Installation
+You can just pick the newest version from the ["Releases" page][releases], or build the software yourself.
+
+### Building
+You will need:
+* cmake
+* make
+* a modern C++ compiler that supports `c++20`
+
+```bash
+# clone the repo
+bash ~/> git clone https://git.mike-ochmann.de/MassiveDynamic/qr.git
+# move into the repository
+bash ~/> cd qr
+# create the build directory and move into it
+bash ~/qr> mkdir build && cd build
+# run `cmake`
+bash ~/qr/build> cmake ..
+# make and install the software
+bash ~/qr/build> make install 
+```
+
+[releases]: releases/