Added opportunity to set fixed amount of promo codes

Added opportunity to set fixed amount of promo codes #38 by @OleksiiBrylin

Laravel 5.8 support fix

2.2.1

5.8 Laravel support

Laravel 5.8 Support

This version supports laravel 5.8

isSecondUsageAttempt method

isSecondUsageAttempt added to check if user is trying to use code for second time

Laravel 5.7 support added

Update composer.json

add support for Laravel 5.7

relationship fix

Merge pull request #28 from abhij89/master

update: bug fix config.php

Cleanup and Fixes

• Code cleanup
• Integrity violation constant error fix

Configuration of pivot table of promocode and user relation

• Added ability to change pivot foreign and related keys
• 2 new parameters in config file

2.0.0: Merge pull request #21 from mpociot/fix-exception-names

Breaking change:

• Updated all exception names as all of them had typo

Support Laravel 5.6

Merge pull request #19 from drolean/master

upgrade to laravel 5.6