feat: consolidate code examples into new file

- Remove an unnecessary line in the README.md file
- Add a new file `_example/example03/main.go`
- Add the same code to `_example/example03/main.go` as in the README.md file
- Update the `_example/example01/main.go` and `_example/example02/main.go` files to match the changes in the README.md file

Signed-off-by: appleboy <appleboy.tw@gmail.com>

README.md

@@ -79,7 +79,6 @@ When you want to skip logging for specific path,
 please use GinzapWithConfig
 
 ```go
-
 r.Use(GinzapWithConfig(utcLogger, &Config{
   TimeFormat: time.RFC3339,
   UTC: true,
@@ -137,6 +136,66 @@ func main() {
   })
 
   // Listen and Server in 0.0.0.0:8080
-  r.Run(":8080")
+  if err := r.Run(":8080"); err != nil {
+    panic(err)
+  }
+}
+```
+
+Example for custom `skipper` function
+
+```go
+r.Use(GinzapWithConfig(logger, &Config{
+  TimeFormat: time.RFC3339,
+  UTC: true,
+  Skipper: func(c *gin.Context) bool {
+    return c.Request.URL.Path == "/ping" && c.Request.Method == "GET"
+  },
+}))
+```
+
+Full example
+
+```go
+package main
+
+import (
+  "fmt"
+  "time"
+
+  ginzap "github.com/gin-contrib/zap"
+
+  "github.com/gin-gonic/gin"
+  "go.uber.org/zap"
+)
+
+func main() {
+  r := gin.New()
+
+  logger, _ := zap.NewProduction()
+
+  r.Use(ginzap.GinzapWithConfig(logger, &ginzap.Config{
+    UTC:        true,
+    TimeFormat: time.RFC3339,
+    Skipper: func(c *gin.Context) bool {
+      return c.Request.URL.Path == "/ping" && c.Request.Method == "GET"
+    },
+  }))
+
+  // Example ping request.
+  r.GET("/ping", func(c *gin.Context) {
+    c.Writer.Header().Add("X-Request-Id", "1234-5678-9012")
+    c.String(200, "pong "+fmt.Sprint(time.Now().Unix()))
+  })
+
+  r.POST("/ping", func(c *gin.Context) {
+    c.Writer.Header().Add("X-Request-Id", "9012-5678-1234")
+    c.String(200, "pong "+fmt.Sprint(time.Now().Unix()))
+  })
+
+  // Listen and Server in 0.0.0.0:8080
+  if err := r.Run(":8080"); err != nil {
+    panic(err)
+  }
 }
 ```

_example/example01/main.go

@@ -35,5 +35,7 @@ func main() {
 	})
 
 	// Listen and Server in 0.0.0.0:8080
-	r.Run(":8080")
+	if err := r.Run(":8080"); err != nil {
+		panic(err)
+	}
 }

_example/example02/main.go

@@ -59,5 +59,7 @@ func main() {
 	})
 
 	// Listen and Server in 0.0.0.0:8080
-	r.Run(":8080")
+	if err := r.Run(":8080"); err != nil {
+		panic(err)
+	}
 }

_example/example03/main.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	ginzap "github.com/gin-contrib/zap"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+)
+
+func main() {
+	r := gin.New()
+
+	logger, _ := zap.NewProduction()
+
+	r.Use(ginzap.GinzapWithConfig(logger, &ginzap.Config{
+		UTC:        true,
+		TimeFormat: time.RFC3339,
+		Skipper: func(c *gin.Context) bool {
+			return c.Request.URL.Path == "/ping" && c.Request.Method == "GET"
+		},
+	}))
+
+	// Example ping request.
+	r.GET("/ping", func(c *gin.Context) {
+		c.Writer.Header().Add("X-Request-Id", "1234-5678-9012")
+		c.String(200, "pong "+fmt.Sprint(time.Now().Unix()))
+	})
+
+	r.POST("/ping", func(c *gin.Context) {
+		c.Writer.Header().Add("X-Request-Id", "9012-5678-1234")
+		c.String(200, "pong "+fmt.Sprint(time.Now().Unix()))
+	})
+
+	// Listen and Server in 0.0.0.0:8080
+	if err := r.Run(":8080"); err != nil {
+		panic(err)
+	}
+}