text: Title: How to login with cookie?
  Body: Hi, I create a login form page , I want to login it with cookie, How to do it? I test it , but not work.
  
  ```
  auth_backends = [
      CookieAuthentication(secret=SECRET, lifetime_seconds=3600),
      # JWTAuthentication(secret=SECRET, lifetime_seconds=3600),
  ]
  
  fastapi_users = FastAPIUsers(
      user_db, auth_backends, User, UserCreate, UserUpdate, UserDB, SECRET,
  )
  app.include_router(fastapi_users.router, prefix="/users", tags=["users"])
  
  templates = Jinja2Templates(directory='templates')
  ...
  
  @app.get("/")
  async def read_root(user: User = Depends(fastapi_users.get_current_active_user)):
      return {"Hello": f"{user.email}"}
  
  
  @app.route("/login", methods=['GET'])
  async def login(request):
      return templates.TemplateResponse('login.html', {'request': request})
  ```
  template
  ```
  <!DOCTYPE html>
  <html lang="en">
  <head>
      <meta charset="UTF-8">
      <title>Login</title>
  </head>
  <body>
  <h1>Login</h1>
  <form method="post" action="/users/login/cookie">
      <input name="username" autocomplete="off">
      <input name="password" autocomplete="off">
      <button>submit</button>
  </form>
  </body>
  </html>
  ```
  
  I access Login page and input username and password, then submit it, response null, then I access homepage "http://127.0.0.1:8000", but still display `{"detail":"Unauthorized"}`