Flask SQLAlchemy created an instance folder?

Flask app.

I have a database using sqlite called market.db. I have configured it in my app.py like this: app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///market.db'

Then when I run flask shell, it created a folder instance/. Then I ran db.create_all(), and that created a database inside of that instance/ folder. I can add items to the database no problems while in the same shell, but I am worried about this being production worthy.

File Hierarchy:

I want to deploy this eventually to a cloud server, and I want people to be able to login and register. What I am worried about is if when a user registers, it will save those changes throughout the entire website, or just on that person’s local machine. I want a way for when a user registers, to allow other people on the website to access those other users, because I will have a table of all of the users. Thank you.

app.py:

from flask import Flask, render_template
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///market.db'
db = SQLAlchemy(app)

class Item(db.Model):
    id = db.Column(db.Integer(), primary_key=True)
    name = db.Column(db.String(length=30), nullable=False, unique=True)
    price = db.Column(db.Integer(), nullable=False)
    barcode = db.Column(db.String(length=12), nullable=False, unique=True)
    description = db.Column(db.String(length=1024), nullable=False, unique=True)

@app.route("/")
@app.route('/home')
def home_page():
    return render_template('home.html')

@app.route('/market')
def market_page():
    items = [
        {'id': 1, 'name': 'Phone', 'barcode': '893212299897', 'price': 500},
        {'id': 2, 'name': 'Laptop', 'barcode': '123985473165', 'price': 900},
        {'id': 3, 'name': 'Keyboard', 'barcode': '231985128446', 'price': 150}
    ]
    return render_template('market.html', items=items)