update readme

Author: mikuso

README.md

@@ -1 +1,24 @@
-modkit
+![Diggers Modkit](docs/logo.png)
+
+# Diggers Modkit
+
+## Installation
+
+* Install NodeJS >= 8.5.0
+* Clone or download the repository
+* `cd diggers-modkit`
+* `npm i`
+
+## Usage
+
+### Unpack
+
+To unpack the existing mod (or unpack the vanilla game files), simply run:
+
+`node mod --unpack <path-to-game-dir>`
+
+### Pack
+
+To package the modified files, run:
+
+`node mod --pack <path-to-game-dir>`