express complex query with json_agg with objection.js

[codelover2k]

hi!
I have the tables users, contacts, permissions, roles, users_roles and roles_permissions.
A user have exactly one contact.
A user can have many roles.
A role can have many permissions.
This is the raw SQL that I am using to get the users, its contact data and all permissions of the user:

SELECT
	users.id,
	users.username,
	contacts.id,
	contacts.salutation,
	contacts.first_name,
	contacts.last_name,
	json_agg(DISTINCT permissions.name)
FROM
	users
	LEFT JOIN contacts
	       ON contacts.user_id = users.id
	LEFT JOIN users_roles
	       ON users_roles.user_id = users.id
	LEFT JOIN roles_permissions
	       ON roles_permissions.role_id = users_roles.role_id
	LEFT JOIN permissions
	       ON permissions.id = roles_permissions.permission_id
WHERE
	users.id = 2
GROUP BY
    users.id,
    contacts.id;

can someone please help me to express this with objection.js?

thanks!