title: ValueError: set the `backend` attribute on the user
body: <p>I have added python-social-auth in my project for social logins. I also have a signup form of my own for new users. For social logins, I added some authentication backends. </p>
  
  <p>Now, the social logins are working fine, but the signup form causes some problems.</p>
  
  <p>After I enter the details, and click signup, this error comes up. </p>
  
  <p>I see in the admin panel, the user was added even after this error.</p>
  
  <pre><code>ValueError: You have multiple authentication backends configured and therefore must provide the `backend` argument or set the `backend` attribute on the user.
  </code></pre>
  
  <p>Now, it is asking me to set the backend attribute of the user. How to set that ?</p>
  
  <p>Here is the view for signup,</p>
  
  <pre><code>def signup(request):
      if request.method == 'POST':
              form  = SignupForm(request.POST)
              if form.is_valid():
                      form.save()
                      username = form.cleaned_data.get('username')
                      raw_pass = form.cleaned_data.get('password')
                      user = authenticate(username=username,password=raw_pass)
                      login(request,user)
                      return redirect('location:get_location')
      else:
              form = SignupForm()
      return render(request, 'signup.html', {'form':form})
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/5iqWm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5iqWm.png" alt="enter image description here"></a></p>