Create a two-tab settings view for macOS

Shared/WriteFreely_MultiPlatformApp.swift

@@ -12,5 +12,12 @@ struct WriteFreely_MultiPlatformApp: App {
         WindowGroup {
             ContentView(postStore: store)
         }
+
+        #if os(macOS)
+        Settings {
+            SettingsView()
+                .frame(minWidth: 300, maxWidth: 600, minHeight: 200, maxHeight: 800)
+        }
+        #endif
     }
 }

macOS/Settings/SettingsView.swift

@@ -0,0 +1,34 @@
+import SwiftUI
+
+struct SettingsView: View {
+    @State var selectedView = 0
+
+    var body: some View {
+        TabView(selection: $selectedView) {
+            AccountLogin()
+                .tabItem {
+                    Image(systemName: "person.crop.circle")
+                    Text("Account")
+                }
+                .tag(0)
+            Preferences()
+                .tabItem {
+                    Image(systemName: "gear")
+                    Text("Preferences")
+                }
+                .tag(1)
+        }
+    }
+}
+
+struct SettingsView_AccountTabPreviews: PreviewProvider {
+    static var previews: some View {
+        SettingsView(selectedView: 0)
+    }
+}
+
+struct SettingsView_PreferencesTabPreviews: PreviewProvider {
+    static var previews: some View {
+        SettingsView(selectedView: 1)
+    }
+}