Eloquent Relationship with ID and link

I would like to create relationship two table with id. I have tables following:

categories

id  |name      |
----------------
1   |Category A|
2   |Category B|
3   |Category C|
4   |Category D|
5   |Category E|

sales
id |customer   |region       |product       |category_id
-------------------------------------------------------
1   James       Region A      Fruits         1,2,5
2   Billy       Region B      Vegetable      3,2,4
3   Benny       Region C      Computer       2,3,1

This is the relation function:

class Category extends Model
{
    public function sales ()
    {
        return $this->hasMany('App\Model\Sale');
    }
}

class Sale extends Model
{
    public function categories ()
    {
        return $this->belongTo('App\Model\Category');
    }
}

Desire result to view is:

customer   |region       |product       |Link to Category
-------------------------------------------------------
James       Region A      Fruits         Category A, Category B, Category E
Billy       Region B      Vegetable      Category C, Category B, Category D
Benny       Region C      Computer       Category B, Category C, Category A

And I want create link in column Link to Category where each category have a link to show category.

Could anyone show the way..? Thanks in advance.