Add README

Author: mpdifran

README.md

@@ -0,0 +1,41 @@
+# AdaptiveTabView
+
+An adaptive SwiftUI container that switches between [TabView](https://developer.apple.com/design/human-interface-guidelines/components/navigation-and-search/tab-bars) and [NavigationSplitView](https://developer.apple.com/design/human-interface-guidelines/components/layout-and-organization/split-views) based on horiontal size class. This framework allows you to easily build iPhone and iPad apps that conform to [Apple's Human Interface Guidelines](https://developer.apple.com/design/).
+
+Here's an example of how it can be used:
+
+```swift
+@main
+struct MyApp: App {
+    var body: some Scene {
+        WindowGroup {
+            AdaptiveTabView(appName: "My App") {
+                MyFirstTab()
+                MySecondTab()
+                MyThirdTab()
+            } defaultContent: {
+                MyDefaultContentView()
+            } defaultDetail: {
+                MyDefaultDetailView()
+            } sidebarExtraContent: {
+                Section {
+                    ForEach(folders) { (folder) in
+                        FolderSidebarCell(folder)
+                    }
+                }   
+            }
+        }
+    }
+}
+```
+
+```swift
+struct MyFirstTab: View, TitleImageProviding {
+    let title = "My First Tab"
+    let systemImageName = "1.square"
+
+    var body: some View {
+        ...
+    }
+}
+```