Update README.md

Author: ocots

README.md

@@ -31,7 +31,7 @@
 [deps-url]: https://juliahub.com/ui/Packages/General/CTModels?t=2
 
 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 model and solve optimal control problems with ordinary differential equations by direct and indirect methods.
+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 model and solve optimal control problems with ordinary differential equations by direct and indirect methods, both on CPU and GPU.
 
 [![doc OptimalControl.jl](https://img.shields.io/badge/Documentation-OptimalControl.jl-blue)](http://control-toolbox.org/OptimalControl.jl)