Appgyver iOS - How to change the default color of selected and unselected iOS tab-bar icons

I need to change the color of the icon on the app's iOS tab-bar. In the previous documentation, it was done as follows ( link ):

steroids.config.tabBar.tintColor = "#00aeef"
steroids.config.tabBar.tabTitleColor = "#ffffff"
steroids.config.tabBar.selectedTabTintColor = "#11aeef"

I tried to do it in the following way (in the file structure.coffee and app.coffee) but without success:

tabBar:
tintColor: "#FFFFFF"
selectedTabTintColor: "#FFFFFF"

Does anyone have any idea how to do this?