Relations for the email_preview permissions are not added during migration

[allouis]

Issue Summary

When upgrading from Ghost 3.0 or lower, the permissions for testing newsletter emails are not correct, and only work for the Owner user.

To Reproduce

1. Create Ghost site on version 3.0
2. Update it to the latest
3. Log into the /ghost as an Administrator or Editor
4. Try to send test newsletter email from post publishing menu

Technical details:

The issue is that the migration here does not add the relation of the permissions to roles, just the permissions.

• Ghost Version: >3.1 if migrated to from <3.1
• Node Version: any
• Browser/OS: any
• Database: any

[allouis]

SELECT
  roles.name,
  permissions.object_type,
  permissions.action_type
FROM
  roles,
  permissions,
  permissions_roles
WHERE
  roles.id = permissions_roles.role_id
AND
  permissions.id = permissions_roles.permission_id
AND
  permissions.object_type = 'email_preview';

Useful snippet to check if the migration has worked correctly