add the Trait "HasDynamicAttributes" to your model
in the method "getDynamicAttributes" return an array with the dynamic attributes and their field types. Available are:
- string
- text
- int
- double
- object
- date
- time
- datetime
Use it as you normally would with static attributes.

Example: If you want your Users Model to have an additional field named "country" with type string: Add HasDynamicAttributes to your User model Make the getDynamicAttributes method return ['country'=>'string']

Set the field by assigning the property to the model:

$user->country='Austria';

Retrieving the Property is about the same:

echo $user->country; // 'Austria'