Connection to MariaDB using Sequelize

I'm using Sequelize and fastify to do an API and would like to not have to log in for every request. So for that I had the idea of connecting when my web server (fastify) starts. But I can't recover the connection with the models etc to use my database in the other files.
Code for connection:

// Start the server
try {
  fastify.listen(config.fastify.server.port, config.fastify.server.host).then(() => {
    console.log(`Server listening on http://${config.fastify.server.host}:${config.fastify.server.port}`)

    // Connection to the database
    this.sequelize = new Sequelize(config.database.name, config.database.user, config.database.password, {
      host: config.database.host,
      dialect: config.database.dialect,
      port: config.database.port,
      connectionLimit: 10,
      pool: {
        max: 5,
        min: 0,
        acquire: 30000,
        idle: 10000
      },
      define: {
        timestamps: false
      }
    });
    this.sequelize.define('User', models.User);
  })
} catch (err) {
  console.log(err)
  process.exit(1)
}