feat(context): add BindQuery func (#1029)

* feat(context): add BindQuery func, only parse/bind the query string params.

* docs(readme): add BindQuery section.

* docs(readme): fix import.

* docs(readme): separate import

README.md

@@ -460,7 +460,43 @@ func main() {
 }
 ```
 
-### Bind Query String
+### Only Bind Query String
+
+`BindQuery` function only binds the query params and not the post data. See the [detail information](https://github.com/gin-gonic/gin/issues/742#issuecomment-315953017).
+
+```go
+package main
+
+import (
+	"log"
+
+	"github.com/gin-gonic/gin"
+)
+
+type Person struct {
+	Name    string `form:"name"`
+	Address string `form:"address"`
+}
+
+func main() {
+	route := gin.Default()
+	route.Any("/testing", startPage)
+	route.Run(":8085")
+}
+
+func startPage(c *gin.Context) {
+	var person Person
+	if c.BindQuery(&person) == nil {
+		log.Println("====== Only Bind By Query String ======")
+		log.Println(person.Name)
+		log.Println(person.Address)
+	}
+	c.String(200, "Success")
+}
+
+```
+
+### Bind Query String or Post Data
 
 See the [detail information](https://github.com/gin-gonic/gin/issues/742#issuecomment-264681292).