apps.dashboard.views & .tests.test_views now take advantage of DUPLICATE_ITEM_ERROR & ExistingListItemForm() from .forms

src/apps/dashboard/views.py

@@ -1,6 +1,6 @@
 from django.core.exceptions import ValidationError
 from django.shortcuts import redirect, render
-from .forms import ItemForm
+from .forms import ExistingListItemForm, ItemForm
 from .models import Item, List
 
 def home_page(request):
@@ -17,10 +17,10 @@ def new_list(request):
 
 def view_list(request, list_id):
     our_list = List.objects.get(id=list_id)
-    form = ItemForm()
+    form = ExistingListItemForm(for_list=our_list)
 
     if request.method == "POST":
-        form = ItemForm(data=request.POST)
+        form = ExistingListItemForm(for_list=our_list, data=request.POST)
         if form.is_valid():
             form.save(for_list=our_list)
             return redirect(our_list)