Update readme

Author: azerupi

README.md

@@ -12,22 +12,28 @@ To have an idea of what a rendered book looks like,take a look at the [**Documen
 
 ## Installation
 
-Before building mdBook, make sure that you installed `stylus` and `nib` from `npm` because it is used to compile the stylesheets
+```
+git clone --depth=1 https://github.com/azerupi/mdBook.git
+cd mdBook
+cargo build --release
+```
+
+The executable `mdbook` will be in the `./target/release` folder, this should be added to the path.
+
+If you want to regenerate the css (stylesheet), make sure that you installed `stylus` and `nib` from `npm` because it is used to compile the stylesheets
 
 Install [node.js](https://nodejs.org/en/)
 
 ```
 npm install -g stylus nib
 ```
 
+Then build with the `regenerate-css` feature:
+
 ```
-git clone --depth=1 https://github.com/azerupi/mdBook.git
-cd mdBook
-cargo build --release
+cargo build --release --features="regenerate-css"
 ```
 
-The executable `mdbook` will be in the `./target/release` folder, this should be added to the path.
-
 ## Structure
 
 There are two main parts of this project: