Fixes and improvements

service/manager/repository/main/sqlite/utils.go

@@ -0,0 +1,16 @@
+package sqlite
+
+import (
+	"encoding/json"
+)
+
+func marshalStringSlice(values []string) (string, error) {
+	if values == nil {
+		values = []string{}
+	}
+	data, err := json.Marshal(values)
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}