Model Initialization Error

import datetime

from flask.ext.bcrypt import generate_password_hash
from flask.ext.login import UserMixin
from peewee import *


DATABASE = SqliteDatabase("tacocat.db")


class User(UserMixin, Model):
    email = CharField(unique = True)
    password = CharField(max_length = 100)

    class Meta:
        database = DATABASE

    @classmethod
    def create_user(cls, email, password):
        try:
            with DATABASE.transaction():
                cls.create(
                    email = email,
                    password = generate_password_hash(password)
                )
        except IntegrityError:
            raise ValueError("User already exists.")


def Taco(Model):
    protein = CharField()
    shell = CharField()
    cheese = BooleanField()
    extras = TextField()

    timestamp = DateTimeField(default = datetime.datetime.now)
    user = ForeignKeyField(
        rel_model = User,
        related_name = "tacos"
    )

    class Meta:
        database = DATABASE


def initialize():
    DATABASE.connect()
    DATABASE.create_tables([User, Taco], safe = True)
    DATABASE.close()

from flask import (Flask, g, render_template, flash, redirect, url_for,
                   abort)
from flask.ext.bcrypt import check_password_hash
from flask.ext.login import (LoginManager, login_user, logout_user,
                             login_required, current_user)

import forms
import models

DEBUG = True
PORT = 8000
HOST = "0.0.0.0"

app = Flask(__name__)
app.secret_key = "asdfkaljf3j2-3$ADGa@#5AF#$TJ(KJ(L:$%:JA))"

login_manager = LoginManager()
login_manager.init_app(app)
login_manager.login_view = "login"

@login_manager.user_loader
def load_user(userid):
    try:
        return models.User.get(models.User.id == userid)
    except models.DoesNotExist:
        return None


@app.before_request
def before_request():
    """Connect to the database before each request."""
    g.db = models.DATABASE
    g.db.connect()
    g.user = current_user


@app.after_request
def after_request(response):
    """Close the database connection after each request."""
    g.db.close()
    return response


@app.route("/register", methods = ("GET", "POST"))
def register():
    form = forms.RegisterForm()
    if form.validate_on_submit():
        flash("Yay, you registered!", "success")
        models.User.create_user(
            email = form.email.data,
            password = form.password.data
        )
        return redirect(url_for("index"))
    return render_template("register.html", form = form)


@app.route("/login", methods=("GET", "POST"))
def login():
    form = forms.LoginForm()
    if form.validate_on_submit():
        try:
            user = models.User.get(models.User.email == form.email.data)
        except models.DoesNotExist:
            flash("Your email or password doesn't match!", "error")
        else:
            if check_password_hash(user.password, form.password.data):
                login_user(user)
                flash("You've been logged in!", "success")
                return redirect(url_for("index"))
            else:
                flash("Your email or password doesn't match!", "error")

    return render_template("login.html", form=form)


@app.route("/logout")
@login_required
def logout():
    logout_user()
    flash("You've been logged out! Come back soon!", "success")
    return redirect(url_for("index"))


@app.route("/")
def index():
    stream = models.Post.select().limit(100)
    return render_template("stream.html", stream = stream)


@app.errorhandler(404)
def not_found(error):
    return render_template("404.html"), 404


if __name__ == "__main__":
    models.initialize()
    try:
        models.User.create_user(
            email = "sam@example.com",
            password = "password"
        )
    except ValueError:
        pass
    app.run(debug = DEBUG, host = HOST, port = PORT)