Use mattermost v5 module (#1192)

vendor/github.com/mattermost/mattermost-server/v5/model/audits.go

@@ -0,0 +1,34 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+import (
+	"encoding/json"
+	"io"
+)
+
+type Audits []Audit
+
+func (o Audits) Etag() string {
+	if len(o) > 0 {
+		// the first in the list is always the most current
+		return Etag(o[0].CreateAt)
+	} else {
+		return ""
+	}
+}
+
+func (o Audits) ToJson() string {
+	if b, err := json.Marshal(o); err != nil {
+		return "[]"
+	} else {
+		return string(b)
+	}
+}
+
+func AuditsFromJson(data io.Reader) Audits {
+	var o Audits
+	json.NewDecoder(data).Decode(&o)
+	return o
+}