app/assets/images/favicon-black/browserconfig.xml.erb
<?xml version="1.0" encoding="utf-8"?>
<browserconfig>
<msapplication>
<tile>
<square150x150logo src="<%= asset_path 'favicon-black/mstile-150x150.png' %>"/>
<TileColor>#000000</TileColor>
</tile>
</msapplication>
</browserconfig>