I'm stuck on the challenge

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

import models
import forms

DEBUG = True
PORT = 8000
HOST = '0.0.0.0'

app = Flask(__name__)
app.secret_key = 'let this be the secret key'

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 database before each request"""
  g.db = models.DATABASE
  g.db.connect()
  g.user=current_user


@app.after_request
def after_request(response):
  """Disconnect from database 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('Registered successfully', '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 don't match", "error")
  else:
      if check_password_hash(user.password, form.password.data):
        login_user(user)
        flash('Logged in successfully', '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('Logged out successfully', 'success')
      return redirect(url_for('index'))

@app.route('/taco', methods=['GET', 'POST'])
@login_required
def taco():
      form = forms.TacoForm()
      if form.validate_on_submit():
        models.Taco.create(user=g.user._get_current_object(),
                           protein=form.protein.data, 
                           shell=form.shell.data, 
                           cheese=form.shell.data, 
                           extras=form.extras.data.strip()
                          )
        flash('Taco has been added', 'success')
        return redirect(url_for('index'))
  return render_template('taco.html', form=form)


@app.route('/')
def index(): 
  tacos = models.Taco.select().limit(10)
  return render_template('index.html', tacos=tacos)


if __name__ == '__main__':
  models.initialize()
  try:
    with models.DATABASE.transaction():
      models.User.create_user(
        email='moyongqaa@gmail.com', 
        password='password'
      )
  except ValueError:
    pass

  app.run(debug=DEBUG, host=HOST, port=PORT)

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

DATABASE = SqliteDatabase('taco.db')

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

    class Meta:
        database = DATABASE

    def get_tacos(self):
        return Taco.select().where(Taco.user == self)

     def get_stream(self):
        return Taco.select().where(Taco.user == self)

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

class Taco(Model):
      user = ForeignKeyField(rel_model=User, related_name='tacos')
      protein = CharField(default=None)
      shell = CharField()
      cheese = BooleanField(default=False)
      extras = TextField()

    class Meta:
        database = DATABASE 

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

from flask_wtf import Form
from wtforms import StringField, PasswordField, BooleanField, TextAreaField
from wtforms.validators import DataRequired, Length, EqualTo, ValidationError, Email
from models import User

def email_exists(form, field):
  if User.select().where(User.email == field.data).exists():
    raise ValidationError('User with that email already exists')

class RegisterForm(Form):  
  email = StringField('Email', validators=[DataRequired(), Email(), email_exists])
  password = PasswordField('Password', validators=[DataRequired(), Length(min=8), EqualTo('password2', message='Passwords must match')])  
  password2 = PasswordField('Confirm Password', validators=[DataRequired()])  

class LoginForm(Form):
  email = StringField('Email', validators=[DataRequired(), Email()])
  password = PasswordField('Password', validators=[DataRequired()])  

class TacoForm(Form):
  protein = StringField('Protein', validators=[DataRequired()])
  shell = StringField('Shell', validators=[DataRequired()])
  cheese = BooleanField('Cheese')
  extras = TextAreaField('Any extras?')