Schema::create('transactions', function ($table) {
    $table->id();
    $table->foreignId('user_id');
    $table->string('request_id')->unique();
    $table->string('type'); // data | airtime
    $table->string('network');
    $table->string('phone');
    $table->decimal('amount', 10, 2);
    $table->string('status')->default('PENDING');
    $table->string('sim_used')->nullable();
    $table->text('response')->nullable();
    $table->timestamps();
});