Added readme

README.md

+D7018E Special Studies RUST
+===========================
+
+Assignment 3
+------------
+
+## Dependencies
+
+Cargo, rustc
+
+See [this guide](https://gitlab.henriktjader.com/d7018e-special-studies-embedded-systems/are_we_embedded_yet/blob/master/doc/Ecosystem.md)
+for instructions.
+
+## Installation
+
+```
+git clone https://gitlab.henriktjader.com/D7018E-SS-RUST/a3_decode.git
+```
+or
+```
+git clone git@gitlab.henriktjader.com:D7018E-SS-RUST/a3_decode.git
+```
+for developers.
+
+
+
+## Usage
+
+### Compile:
+
+```
+cargo build
+```
+
+### Run:
+
+```
+cargo run
+```
+
+## Description
+
+Will take the string from CODED and output the decoded string into PLAIN