initial code (#6)

* initial code commit

cache/get.go

@@ -0,0 +1,22 @@
+package cache
+
+import (
+	"fmt"
+	"github.com/xujiajun/nutsdb"
+)
+
+func (c *Client) Get(bucket string, key string) ([]byte, error) {
+	var value []byte
+	if err := c.db.View(func(tx *nutsdb.Tx) error {
+		e, err := tx.Get(bucket, []byte(key))
+		if err != nil {
+			return fmt.Errorf("%v: %v; get: %w", bucket, key, err)
+		}
+		value = e.Value
+		return nil
+	}); err != nil {
+		return nil, err
+	}
+
+	return value, nil
+}