How to dynamically add items to VStack from list in SwiftUI

Issue #678

Use enumerated to get index so we can assign to item in list. Here is how I show list of device tokens in my app Push Hero

private var textViews: some View {
    let withIndex = input.deviceTokens.enumerated().map({ $0 })
    let binding: (Int, Input.DeviceToken) -> Binding<String> = { index, token in
        Binding<String>(
            get: { token.token },
            set: { self.input.deviceTokens[index].token = $0 }
        )
    }

    return VStack {
        ForEach(withIndex, id: \.element.id) { index, token in
            return DeviceTokenTextView(text: binding(index, token))
        }
    }
}