must either be declared abstract or implement abstract method 'sendMessage(String)' in 'CommandSender' code example

Example: Class must be declared abstract or implement methods 'hasVerifiedEmail'

You need to either extend Illuminate\Foundation\Auth\User instead of 
Illuminate\Database\Eloquent\Model, or use Illuminate\Auth\Authenticatable 
trait in your class

You need to extend Illuminate\Foundation\Auth\User like this

use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable
{

}