title: How can I fix Django error MultiValueDictKeyError
body: <p>I try to log a user but I have this error: MultiValueDictKeyError at / "'username'". I followed django documentation: <a href="https://docs.djangoproject.com/en/1.7/topics/auth/default/#django.contrib.auth.decorators.login_required" rel="nofollow">https://docs.djangoproject.com/en/1.7/topics/auth/default/#django.contrib.auth.decorators.login_required</a></p>
  
  <p>views:</p>
  
  <pre><code>def home(request):
  
      return render_to_response('home.html', {}, context_instance=RequestContext(request))
  
  
  def login_user(request):
      username = request.POST['username']
      password = request.POST['password']
      user = authenticate(username=username, password=password)
      if user is not None:
          if user.is_active:
              login(request, user)
              return HttpResponseRedirect('start.html')
          else:
              return HttpResponseRedirect('profile.html')
      else:
          return HttpResponseRedirect('home.html')
  </code></pre>
  
  <p>url:</p>
  
  <pre><code> url(r'^$', 'core.views.login_user', name='login_user'),
  </code></pre>
  
  <p>html:</p>
  
  <pre><code>&lt;form action="/login_user" method="POST" name="auth"&gt;
    {% csrf_token %}
    &lt;label&gt;Email&lt;/label&gt;
    &lt;input type="text" name="username"&gt;
    &lt;label&gt;Password&lt;/label&gt;
    &lt;input type="password" name="password"&gt;
    &lt;button type="submit"&gt;Login&lt;/button&gt;
  &lt;/form&gt;
  </code></pre>