How to represent an ordered recursive relationship in Laravel?

Schema

I have the following database schema:

=== modules ===
id: PK
name: String
current_revision: FK to revisions.id

=== revisions ===
id: PK
module_id: unsigned int, indexed, FK to modules.id
parent_revision: unsigned int, nullable, indexed, FK to revisions.id
content: string

Example Data

Example data

modules:

(1, "Maths, 3)
(2, "Computing", 5)

revisions:

(1, 1, null, "Maths - v1")
(2, 1, 1, "Maths- v2")
(3, 1, 2, "Maths - v3")
(4, 2, null, "Computing - v1")
(5, 2, 4, "Computing - v2")

Explanation

As you can see, the parent_revision relates to the previous version of that module or null if it's the first version for the module.

The current_revision relates to the latest version for the category

What I want?

I wish to represent this relationship as a model in Laravel. I managed to make a start:

class Module extends Model
{
    public function currentRevision()
    {
        return $this->belongsTo(Revision::class, 'current_revision_id');
    }

    public function revisions()
    {
       /* Help! (I wish to return all the revisions for this module in
       order, starting from the current_revision. e.g. for the "Maths" 
       module it 
       should return the revisions with IDs: [3, 2, 1] and for the 
       "Computing" module it should return: [4, 3] )*/
    }
}

-

class Revision extends Model
{
    public function module()
    {
        return $this->belongsTo(Module::class);
    }

    public function nextRevision()
    {
        return $this->hasOne(Revision::class, 'parent_revision');
    }

    public function previousRevision()
    {
        return $this->belongsTo(Revision::class, 'parent_revision');
    }

    public function previousRevisions()
    {
        // TODO: return ALL previous revisions
    }
}

I wish to find an efficient way to create the revisions() method for the Module model. How can I do this?

NOTE: I don't mind if you suggest schema changes, provided it is better than what I have currently!

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