fix example and new feature

app/user/model/exampleModel.go

@@ -0,0 +1,27 @@
+package model
+
+import (
+	"github.com/zeromicro/go-zero/core/stores/cache"
+	"github.com/zeromicro/go-zero/core/stores/sqlx"
+)
+
+var _ ExampleModel = (*customExampleModel)(nil)
+
+type (
+	// ExampleModel is an interface to be customized, add more methods here,
+	// and implement the added methods in customExampleModel.
+	ExampleModel interface {
+		exampleModel
+	}
+
+	customExampleModel struct {
+		*defaultExampleModel
+	}
+)
+
+// NewExampleModel returns a model for the database table.
+func NewExampleModel(conn sqlx.SqlConn, c cache.CacheConf) ExampleModel {
+	return &customExampleModel{
+		defaultExampleModel: newExampleModel(conn, c),
+	}
+}