Add additional methods

context.go

@@ -116,3 +116,12 @@ func (c *Context) Redirect(url string) {
 func (c *Context) QueryValue(key string) string {
 	return c.r.URL.Query().Get(key)
 }
+
+func (c *Context) QueryValueWithDefault(key string, def string) string {
+	val := c.r.URL.Query().Get(key)
+	if val == "" {
+		return def
+	}
+	return val
+}
+