Appgyver iOS - How to change the default color of selected and not selected from tab-bar icons on iOS

Question

I need to change the color of the icon that is in the app’s tab-bar on iOS. In the previous documentation, it was done as follows (https://academy.appgyver.com/guides/129-basic-app-settings-in-configapplicationcoffee):

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

I tried to do it as follows (in the file Structure.coffee and app.coffee) but without success:

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

Does anyone have any idea how to make this configuration?