add readme

README.md

+# spectrodraw
+
+Spectrodraw is a command line utility for turning images into audio files. When these audio files are passed through a spectrogram, it will recreate the original image.
+
+Original image:
+
+![](example/amogus.png)
+
+Generate audio file: `spectrodraw -- amogus.png amogus.wav`
+
+Output wav file:
+
+![example/amogus.wav]
+
+Generate spectrogram: `audioprism amogus.wav out.png`
+
+Output spectrogram:
+
+![example/out.png]
+
+Spectrodraw has command line arguments to fine-tune most attributes. It also features optional morse code identification (useful for ham radio transmissions) and repetition of the output.
+
+## Installation
+
+If you have cargo, install with `cargo install spectrodraw`.
+
+If you don't have cargo, download the binary file from the [CI artifact](https://gitlab.scd31.com/stephen/spectrodraw/repository/master/archive.zip).