update README.md add usage

README.md

@@ -1,3 +1,37 @@
 # SwiftUIPullToRefresh
 
-A description of this package.
+
+## Usage
+
+```swift
+import SwiftUI
+import SwiftUIPullToRefresh
+
+
+struct ExamplePullToRefreshView: View {
+    @State private var isRefreshing = false
+    @State private var array: [String] = []
+    var body: some View {
+        NavigationView {
+            List(array, id: \.self) { text in
+                Text(text)
+            }
+            .navigationBarTitle("SwiftUIPullToRefresh")
+            .navigationBarTitleDisplayMode(.inline)
+            .onPullToRefresh(isRefreshing: $isRefreshing, perform: {
+                DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
+                    self.isRefreshing = false
+                    self.array.insert(Date().description, at: 0)
+                }
+            })
+        }
+    }
+}
+
+
+struct ExamplePullToRefreshView_Previews: PreviewProvider {
+    static var previews: some View {
+        ExamplePullToRefreshView()
+    }
+}
+```