Get the count of the all system users at endpoint /users/stats (#8847)

* Get the count of the all system users at endpoint /users/stats

* Added GetTotalUsersStats test in api4

* Changed pluralization and added the test back.

model/client4.go

@@ -392,6 +392,10 @@ func (c *Client4) GetTeamSchemeRoute(teamId string) string {
 	return fmt.Sprintf(c.GetTeamsRoute()+"/%v/scheme", teamId)
 }
 
+func (c *Client4) GetTotalUsersStatsRoute() string {
+	return fmt.Sprintf(c.GetUsersRoute() + "/stats")
+}
+
 func (c *Client4) DoApiGet(url string, etag string) (*http.Response, *AppError) {
 	return c.DoApiRequest(http.MethodGet, c.ApiUrl+url, "", etag)
 }
@@ -1468,6 +1472,17 @@ func (c *Client4) GetTeamStats(teamId, etag string) (*TeamStats, *Response) {
 	}
 }
 
+// GetTotalUsersStats returns a total system user stats.
+// Must be authenticated.
+func (c *Client4) GetTotalUsersStats(etag string) (*UsersStats, *Response) {
+	if r, err := c.DoApiGet(c.GetTotalUsersStatsRoute(), etag); err != nil {
+		return nil, BuildErrorResponse(r, err)
+	} else {
+		defer closeBody(r)
+		return UsersStatsFromJson(r.Body), BuildResponse(r)
+	}
+}
+
 // GetTeamUnread will return a TeamUnread object that contains the amount of
 // unread messages and mentions the user has for the specified team.
 // Must be authenticated.

model/users_stats.go

@@ -0,0 +1,24 @@
+// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"encoding/json"
+	"io"
+)
+
+type UsersStats struct {
+	TotalUsersCount int64 `json:"total_users_count"`
+}
+
+func (o *UsersStats) ToJson() string {
+	b, _ := json.Marshal(o)
+	return string(b)
+}
+
+func UsersStatsFromJson(data io.Reader) *UsersStats {
+	var o *UsersStats
+	json.NewDecoder(data).Decode(&o)
+	return o
+}