Update README.md

Author: IharYakimush

README.md

@@ -1,2 +1,41 @@
 # AspNetCore-ExceptionHandling
 Middleware to configure exception handling policies. Configure chain of handlers per exception type. OOTB handlers: log, retry, set responce headers and body
+
+### Sample
+```
+public void ConfigureServices(IServiceCollection services)
+{
+    services.AddMvc();
+
+    services.AddExceptionHandlingPolicies(options =>
+    {
+        options.For<InitializationException>().Rethrow();
+                
+        options.For<SomeTransientException>().Retry().NextChain();
+                
+        options.For<SomeBadRequestException>()
+            .Response(e => 400)
+                .Headers((h, e) => h["X-MyCustomHeader"] = e.Message)
+                .WithBody((req,sw, exception) => sw.WriteAsync(exception.ToString()))
+            .NextChain();
+
+        // Ensure that all exception types are handled by adding handler for generic exception at the end.
+        options.For<Exception>()
+            .Log(lo =>
+                {
+                    lo.EventIdFactory = (c, e) => new EventId(123, "UnhandlerException");
+                    lo.Category = (context, exception) => "MyCategory";
+                })
+            .Response(e => 500, ResponseAlreadyStartedBehaviour.GoToNextHandler)
+                .ClearCacheHeaders()
+                .WithObjectResult((r, e) => new { msg = e.Message, path = r.Path })
+            .Handled();
+    });
+}
+
+public void Configure(IApplicationBuilder app, IHostingEnvironment env)
+{
+    app.UseExceptionHandlingPolicies();
+    app.UseMvc();
+}
+```