So, I am new to git and Heroku. I have successfully deployed an app to Heroku using git (because Heroku requires git for the free tier). I'd like to start alpha testing soon. However, I don't think I'm quite ready since I don't understand how the interaction between git, Heroku, and my local machine works.
For example, I'll visit the live app at Heroku and make some changes to the sqlite3 database. Later, I'll make a change to one HTML file on my local machine. Then I'll use git add, git commit, and git push heroku master in order to update that HTML file on the live app.
What appears to be happening is all of the files are being rebuilt from my local machine and redeployed at Heroku which wipes any changes that I've made to the sqlite3 database.
How do I get around this?