UserManager => Add get staff function

ExpressAPI/src/managers/UserManager.ts

 import User        from '../models/User';
 import db          from '../helpers/DatabaseHelper';
 import GitlabUser  from '../shared/types/Gitlab/GitlabUser';
+import EnonceStaff from '../models/EnonceStaff';
 
 
 class UserManager {
@@ -62,6 +63,14 @@ class UserManager {
     async getFromGitlabUsers(gitlabUsers: Array<GitlabUser>, createIfNotExist: boolean = false): Promise<Array<User | number>> {
         return Promise.all(gitlabUsers.map(gitlabUser => this.getFromGitlabUser(gitlabUser, createIfNotExist)));
     }
+
+    async getStaffOfEnonce(enonceName: string): Promise<Array<User>> {
+        const raw = await db<User>(User.tableName)
+        .innerJoin(EnonceStaff.tableName, `${ EnonceStaff.tableName }.userId`, `${ User.tableName }.userId`)
+        .where('enonceName', enonceName);
+
+        return raw ? raw.map(user => this.createObjectFromRawSql(user)) : [];
+    }
 }