My logout button wont appear once user is authenticated

 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,
                         current_user,login_required)
import models
import forms

DEBUG = True
PORT = 8000
HOST = '0.0.0.0'


app = Flask(__name__)
app.secret_key = 'rfhrfuwn3ofi39-fh'
login_manager = LoginManager()
login_manager.init_app(app)
login_manager.login_view = 'login'

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

@app.before_request
def before_request():
  g.db = models.DATABASE
  g.db.connect()
  g.user = current_user

@app.after_request
def after_request(response):
  g.db.close()
  return response

@app.route('/register',methods=('GET','POST'))
def register():
  form = forms.Registration()
  if form.validate_on_submit():
    flash('You just 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.select().where(
                models.User.email**form.email.data
            ).get()
            if check_password_hash(user.password, form.password.data):
                login_user(user)
                flash("You're now logged in!")
                return redirect(url_for('index'))
            else:
                flash("Email or password is invalid")
        except models.DoesNotExist:
            flash("Email or password is invalid")
    return render_template('login.html', form=form)

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


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



if __name__== '__main__':
  models.initialize()
  app.run(debug=DEBUG,port=PORT,host=HOST)

<div class="container">
  <div class="row">
    <div class="u-full-width">
      <nav class="menu">

        {% if current_user.is_authenticated() %}
            <a href="{{ url_for('logout') }}" class="icon-power" title="Log out">Logout</a>
            {% else %}
            <a href="{{ url_for('login') }}" class="icon-power" title="Log in">Login</a>
            <a href="{{ url_for('register') }}" class="icon-profile" title="Register">Register</a>
            {% endif %}

      <!-- menu goes here -->
      </nav>
      {% block content %}{% endblock %}
    </div>
  </div>
  <footer>
    <p>An MVP web app made with Flask on <a href="http://teamtreehouse.com">Treehouse</a>.</p>
  </footer>
</div>