Removed unused fields from ChannelMemberHistory table, introduced new model.ChannelMemberHistoryResult object that includes those fields that are selected from a join on other tables

model/ChannelMemberHistoryResult.go

@@ -0,0 +1,15 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+type ChannelMemberHistoryResult struct {
+	ChannelId string
+	UserId    string
+	JoinTime  int64
+	LeaveTime *int64
+
+	// these two fields are never set in the database - when we SELECT, we join on Users to get them
+	UserEmail string `db:"Email"`
+	Username  string
+}

model/channel_member_history.go

@@ -8,8 +8,4 @@ type ChannelMemberHistory struct {
 	UserId    string
 	JoinTime  int64
 	LeaveTime *int64
-
-	// these two fields are never set in the database - when we SELECT, we join on Users to get them
-	UserEmail string `db:"Email"`
-	Username  string
 }