version: "3.8"

services:

  mantisbt:
    image: vimagick/mantisbt
    ports:
      - "8989:80"
    depends_on:
      - mysql
    restart: unless-stopped

  mysql:
    image: mysql
    volumes:
      - ./data:/var/lib/mysql
    environment:
      - MYSQL_ROOT_PASSWORD=root
      - MYSQL_DATABASE=bugtracker
      - MYSQL_USER=mantis
      - MYSQL_PASSWORD=mantis
    restart: unless-stopped

You can use mariadb/postgres instead of mysql.

install

$ firefox http://localhost:8989/admin/install.php
>>> username: administrator
>>> password: root

==================================================================================
Installation Options
==================================================================================
Type of Database                                        MySQL/MySQLi
Hostname (for Database Server)                          mysql
Username (for Database)                                 mantisbt
Password (for Database)                                 mantisbt
Database name (for Database)                            bugtracker
Admin Username (to create Database if required)         root
Admin Password (to create Database if required)         root
Print SQL Queries instead of Writing to the Database    [ ]
Attempt Installation                                    [Install/Upgrade Database]
==================================================================================

email

Append following to /var/www/html/config_inc.php

$g_phpMailer_method = PHPMAILER_METHOD_SMTP;
$g_administrator_email = 'admin@example.org';
$g_webmaster_email = 'webmaster@example.org';
$g_return_path_email = 'mantisbt@example.org';
$g_from_email = 'mantisbt@example.org';
$g_smtp_host = 'smtp.example.org';
$g_smtp_port = 25;
$g_smtp_connection_mode = 'tls';
$g_smtp_username = 'mantisbt';
$g_smtp_password = '********';