I'm using `react-toolbox` for my project.

I have tried some feature that it has, i.e icon button. and now i need a button with `arrow-u`p icon. i dont know whether it is provided by react-toolbox or not.

`<Button icon='arrow-up' floating />`

The code above doesnt show any icon on the button

How do I use the `arrow-up` icon? Any help is appreciated