Prerequisites
Use the identify static method in Castled SDK to create/update users with their unique traits. The data sent via identify will be stored in your data warehouse. 
Castled::identify([
        'userId' => '12345',
        'traits' => [
            'plan' => 'basic',
            'first_name' => 'John',
            'last_name' => 'Taylor'
        ]
    ]);