So, okay i tried a lot of rules from validation docs but all give me same error saying
Array to string conversion
Here is how I add
Implode the array as a string and join it on commas.
'employee' => 'required|in:'.$employee->implode('id', ', '),
This will make the correct comma separated string that the validator expects when making an in
comparison.
Edit
This still works, but is not the Laravelesque way of doing it anymore. See the answer by @nielsiano.