title: Express session using redis store couldn't create session
body: <p>I'm using Express 4.13.1 with Redis as session store.</p>
  
  <pre><code>app.use(session({
      store: new RedisStore,
      secret: '...',
      resave: false,
      saveUninitialized: true
  }));
  </code></pre>
  
  <p>It worked at first, but then it didn't work (after upgrading node.js). Using default store(memory) works fine, but using RedisStore, session is not being created. This is the code to create session :</p>
  
  <pre><code>router.post('/admin/login', (req, res, next) =&gt; {
      Auth.compare(..., () =&gt; {
          req.session.authorized = true;
          req.session.userId = id;
  
          console.log(req.session);    // It prints well. Session is created
  
          res.redirect('/admin/main');
      });
  });
  </code></pre>
  
  <p>at that moment, session was changed:</p>
  
  <pre><code>Session {
    cookie: 
     { path: '/',
       _expires: null,
       originalMaxAge: null,
       httpOnly: true },
    authorized: true,
    userId: '...'}
  </code></pre>
  
  <p>but after that, session wasn't created:</p>
  
  <pre><code>router.get('/admin/main', (req, res, next) =&gt; {
      console.log(req.session);
      ...
  });
  </code></pre>
  
  <p>printing session:</p>
  
  <pre><code>Session {
    cookie: 
     { path: '/',
       _expires: null,
       originalMaxAge: null,
       httpOnly: true }
  }
  </code></pre>
  
  <p>I used session.save manually, but it didn't work. What am I missing?</p>