How do I solve this problem

from shop import db
import datetime

class Addproduct(db.Model):
    id = db.Column(db.Integer,primary_key=True)
    name = db.Column(db.String(80), nullable=False)
    price = db.Column(db.Numeric(10,2),nullable=False)
    discount = db.Column(db.Integer,default=0)
    stock = db.Column(db.Integer,nullable=False)
    colors = db.Column(db.Text,nullable=False)
    desc = db.Column(db.Text,nullable=False)
    pub_date = db.Column(db.DateTime,nullable=False)

    brand_id = db.Column(db.Integer,db.ForeignKey('brand.id'),nullable=False)
    brand = db.relationship('Brand',backref=db.backref('brand',lazy=True))

    category_id = db.Column(db.Integer,db.ForeignKey('category.id'),nullable=False)
    category = db.relationship('Category',backref=db.backref('posts',lazy=True))

    image_1 = db.Column(db.String(150),nullable=False,default='image.jpg')
    image_2 = db.Column(db.String(150),nullable=False,default='image.jpg')
    image_3 = db.Column(db.String(150),nullable=False,default='image.jpg')

    def __repr__(self):
        return '<addproduct %r="">' % self.name



class Brand(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(30), nullable=False, unique=True)

class Category(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(30), nullable=False, unique=True)

db.create_all()



ROOTS.PY
from flask import redirect, render_template, url_for, flash, request
from shop import db, app, photos
from .models import Brand, Category
from .forms import Addproduct

@app.route('/addbrand', methods=['GET','POST'])
def addbrand():
    if request.method=="POST":
        getbrand = request.form.get('brand')
        brand = Brand(name=getbrand)
        db.session.add(brand)
        flash(f'The Brand {getbrand} was added to your database','success')
        db.session.commit()
        return redirect(url_for('addbrand'))
    return render_template('products/addbrand.html', brands='brands')

@app.route('/addcat', methods=['GET','POST'])
def addcat():
    if request.method=="POST":
        getbrand = request.form.get('category')
        cat = Category(name=getbrand)
        db.session.add(cat)
        flash(f'The Category {getbrand} was added to your database','success')
        db.session.commit()
        return redirect(url_for('addcat'))
    return render_template('products/addbrand.html')

@app.route('/Addproduct', methods=['GET','POST'])
def addproduct():
    brands = Brand.query.all()
    categories = Category.query.all()
    form = Addproduct(request.form)
    if request.method == "POST":
        photos.save(request.files.get('images_1'))
        photos.save(request.files.get('images_2'))
        photos.save(request.files.get('images_3'))
    return render_template('products/addproduct.html', title="Add Product page", form= form,brands=brands,categories=categories)