Add missing docstrings for registration views

The missing docstrings are annoying when using autogenerated schemas with swagger or similar api documentation tools

dj_rest_auth/registration/views.py

@@ -32,6 +32,11 @@
 
 
 class RegisterView(CreateAPIView):
+    """
+    Registers a new user.
+
+    Accepts the following POST parameters: username, email, password1, password2.
+    """
     serializer_class = api_settings.REGISTER_SERIALIZER
     permission_classes = api_settings.REGISTER_PERMISSION_CLASSES
     token_model = TokenModel
@@ -96,6 +101,12 @@ def perform_create(self, serializer):
 
 
 class VerifyEmailView(APIView, ConfirmEmailView):
+    """
+    Verifies the email associated with the provided key.
+
+    Accepts the following POST parameter: key.
+    """
+
     permission_classes = (AllowAny,)
     allowed_methods = ('POST', 'OPTIONS', 'HEAD')
 
@@ -115,6 +126,11 @@ def post(self, request, *args, **kwargs):
 
 
 class ResendEmailVerificationView(CreateAPIView):
+    """
+    Resends another email to an unverified email.
+
+    Accepts the following POST parameter: email.
+    """
     permission_classes = (AllowAny,)
     serializer_class = ResendEmailVerificationSerializer
     queryset = EmailAddress.objects.all()