Update README.md

Author: ocots

README.md

@@ -18,6 +18,9 @@
 [aqua-img]: https://raw.githubusercontent.com/JuliaTesting/Aqua.jl/master/badge.svg
 [aqua-url]: https://github.com/JuliaTesting/Aqua.jl
 
+[blue-img]: https://img.shields.io/badge/code%20style-blue-4495d1.svg
+[blue-url]: https://github.com/JuliaDiff/BlueStyle
+
 This repo is part of the [control-toolbox ecosystem](https://github.com/control-toolbox). 
 The control-toolbox ecosystem gathers Julia packages for mathematical control and applications. The root package is [OptimalControl.jl](https://github.com/control-toolbox/OptimalControl.jl) which aims to provide tools to modelise and solve optimal control problems with ordinary differential equations by direct and indirect methods. 
 
@@ -26,7 +29,7 @@ The control-toolbox ecosystem gathers Julia packages for mathematical control an
 | **Name**          | **Badge**         |
 :-------------------|:------------------|
 | Documentation     | [![Documentation][doc-stable-img]][doc-stable-url] [![Documentation][doc-dev-img]][doc-dev-url]                   | 
-| Code Status       | [![Build Status][ci-img]][ci-url] [![Covering Status][co-img]][co-url] [![Aqua.jl][aqua-img]][aqua-url] |
+| Code Status       | [![Build Status][ci-img]][ci-url] [![Covering Status][co-img]][co-url] [![Aqua.jl][aqua-img]][aqua-url] [![Code Style: Blue][blue-img]][blue-url] |
 | Licence           | [![License: MIT][licence-img]][licence-url]   |
 
 ## Contributing