improve readme, closes #2

README.md

@@ -3,8 +3,46 @@
 Lamp is a backlight control program written in Rust and inspired by
 [acpibacklight](https://gitlab.com/wavexx/acpilight).
 
+## Features
+
+In contrast to acpilight lamp is not backwards compatible with xbacklight.
+It is intended to be used as a standalone replacement for new scripts.
+
+```none
+    -d, --decrease <PERCENT>        Decreases brightness
+    -f, --full                      Sets brightness to highest value
+    -g, --get                       Prints current brightness value
+    -h, --help                      Print help information
+    -i, --increase <PERCENT>        Increases brightness
+    -l, --list                      Lists all available brightness and led controllers
+    -s, --set <VALUE>               Sets brightness to given value
+    -t, --type <controller_type>    choose controller type [default: lin] [possible values: raw,
+                                    lin, log]
+    -V, --version                   Print version information
+    -z, --zero                      Sets brightness to lowest value
+```
+
 ## Install
 
 Binary packages for the following systems are currently available.
 
 [![Packaging status](https://repology.org/badge/vertical-allrepos/lamp.svg)](https://repology.org/project/lamp/versions)
+
+You can also install it via `cargo`:
+
+```bash
+cargo install lamp
+```
+
+You have to make sure, that you have write access to `/sys/class/backlight/`.
+This can be achieved by using udev rules like `90-backlight.rules` in this repo.
+
+## Build
+
+lamp is a pure Rust project so you can simply run `cargo build` after installing the Rust toolchain.
+
+Formatting is done via `cargo fmt` with the default rules and in the pipeline `clippy` is run with the following arguments:
+
+```bash
+cargo clippy -- --deny clippy::all --deny warnings
+```