Comenzando a utilizar SQLAlchemy

Tuve que reescribir bastante para lograrlo, pero ya funciona :3

files/commands.py

@@ -0,0 +1,90 @@
+import click
+import os
+
+from flask import current_app
+from flask.cli import with_appcontext
+
+from werkzeug.security import generate_password_hash
+
+from files.models import db, User, Category, File
+
+
+def init_db():
+    db.drop_all()
+    db.create_all()
+
+
+def generate_admin():
+    username = current_app.config['USERNAME']
+    password = current_app.config['PASSWORD']
+
+    u = User(username, generate_password_hash(password))
+    db.session.add(u)
+    db.session.commit()
+
+
+def add_defaults():
+    default_category = Category('Default')
+    db.session.add(default_category)
+    db.session.commit()
+
+
+def add_files():
+    existing_files = os.listdir(current_app.config['UPLOAD_FOLDER'])
+    default_category = Category.query.filter_by(name='Default').first()
+    added = 0
+
+    for f in existing_files:
+        search = File.query.filter_by(filename=f).first()
+        if search is None:
+            file = File(f, 0, default_category.id)
+            db.session.add(file)
+            added += 1
+    db.session.commit()
+
+    return added
+
+
+@click.command('init-db')
+@with_appcontext
+def init_db_command():
+    """
+    Creates the db file
+    """
+    init_db()
+
+
+@click.command("add-defaults")
+@with_appcontext
+def add_defaults_command():
+    """
+    Initializes the database with default data
+    """
+    add_defaults()
+    click.echo("Defaults added")
+
+
+@click.command('generate-admin')
+@with_appcontext
+def generate_admin_command():
+    """Creates the admin of the system"""
+    generate_admin()
+    click.echo('The admin was created')
+
+
+@click.command('add-files')
+@with_appcontext
+def add_files_command():
+    """
+    Generates the rows in the database for the files currently uploaded
+    They all will have default privacy, so, public
+    """
+    added_size= add_files()
+    click.echo(f'added {added_size} files')
+
+
+def init_app(app):
+    app.cli.add_command(init_db_command)
+    app.cli.add_command(add_defaults_command)
+    app.cli.add_command(generate_admin_command)
+    app.cli.add_command(add_files_command)