Modify PersonalAccessToken Model to be polymorphic

[amaelftah]

this PR resolves #10 .

by making PersonalAccessToken model polymorphic will allow multiple models to be authenticated through airlock tokens .

for example if i have Pharmacist & Doctor models . and would authenticate both of them through api . i would have to implement this solution which is in my opinion a little bit tedious .

but by making PersonalAccessToken model polymorphic. this will allow implementing the above use case without any extra boilerplate .

and also customization to user Model through userModel() won't be needed any more . cause polymorphic relation will support any other models .

[taylorotwell]

I think I would suggest renaming even the user relationship on the model to something like tokenable and then having tokenable_id and tokenable_type as the morph columns.

[amaelftah]

@taylorotwell Done . and i thnk you are right since the token now belongs to multiple different models .

[rgr]

Is there a way to use sanctum without morphing features to save database space and keep a basic user_id column ?