You saw the LICENSE but you were like TL;DR. Here's what the license entails:
1. You have to include the license and copyright notice with each and every distribution/code base.
2. This sofware can be copied, modified and distrubuted by anyone. Or be used privately if need be.
3. If you modifiy it, you have to indicate changes made to the code.
4. Any modifications of this code base MUST be distributed with the same license, GPLv3.
5. You can use this sofware for commercial purposes.
6. You have to opensource any code on top of this software, whether your business is running on it or not.
7. This sofware is provided without warranty and the software author/license can not be held liable for any damages.
@imagtek Know the version of your license. Is it GPLv3.0? If so, it may not forgiving unfortunately. If you use it within your service, it may affect all the code.