How to add likes meter on a social media app

I’m working on a social media app right now and have stumbled upon my first major challenge.
The like meter, I’m using Firebase as my storage and was thinking of adding the likes in the tag itself.

My tags for posts are this way
<url of cloudinary(where I’m storing the images)>

this is my tag, i use tags this way cause its easier and faster to retrieve data this way(open to suggestions if any more efficient way is available)

The problem with this is i was deleting the tag with old votes and adding new tag with new votes but this way if I have multiple users online i may have a huge problem, so please help me.

Thank you in advance

I can use that method but the thing is that every post has different number of likes…