​Employing a recovered addict. Anything I should be thinking of?

I recently promoted an assembly employee to a shift-manager position after 6 months on the job. During the meeting she broke down crying, telling me how thankful she is for the position and giving me the story of how this is her first stable job ever after spending years as a drug addict, homeless for a part of it.

It wasn’t a huge shock and I kind of knew she had a rough past; it was very touching, but also made me wonder if there are some things I should be cautious of, as this isn’t some far-away past but something that was still going on a couple of years ago.

To be clear- she’s a great worker, hard-working, always on time, truly cares about the work she does and pleasent with her team members. I’m happy to have her around have no intention to do anything negative about that, but I come from a country were drugs weren’t much of a thing and I’m not sure if there are things I should be alert for as signs or relapse and what to do if they come.

EDIT: A lot of people replied about treating her as a person, and I agree with you 100%. I have no intention to judge her or alter her job or progression in any way due to this. I do want to be sensitive to the situation though, to be able to support her and to protect my business and other employees.