remove list from group when changing curation

Allows 'group' to be blank when saving a list.
Removes the 'group' field when saving a list with curation other than 'group' - this stops the list "sticking" to a group after it is changed from group curation to something else.

bookwyrm/models/list.py

@@ -37,7 +37,8 @@ class List(OrderedCollectionMixin, BookWyrmModel):
     group = models.ForeignKey(
         "Group",
         on_delete=models.CASCADE,
-        null=True
+        default=None,
+        blank=True
     )
     books = models.ManyToManyField(
         "Edition",

bookwyrm/templates/lists/form.html

@@ -37,20 +37,16 @@
               <input type="radio" name="curation" value="group"{% if list.curation == 'group' %} checked{% endif %}> {% trans "Group" %}
               <p class="help mb-2">{% trans "Group members can add to and remove from this list" %}</p>
           </label>
-
           <!-- TODO: add a list picker on-select for group lists -->
-
-          <!-- TODO: change the submission url -->
-          <!-- <form name="list-add" method="post" action="{% url 'list-add-book' %}"> -->
             {% if user_groups %}
               {% csrf_token %}
               <label class="label" for="id_group">{% trans "Select Group" %}</label>
               <div class="field has-addons">
                   <div class="select control">
                       <select name="group" id="id_group">
-                          <option value="{{ group.id }}" disabled selected></option>
+                          <option value="">Select a list</option>
                           {% for group in user_groups %}
-                          <option value="{{ group.id }}">{{ group.name }}</option>
+                          <option value="{{ group.id }}" {% if list.group.id == group.id %} selected{% endif %}>{{ group.name }}</option>
                           {% endfor %}
                       </select>
                   </div>

bookwyrm/views/list.py

@@ -62,10 +62,6 @@ class Lists(View):
     def post(self, request):
         """create a book_list"""
         form = forms.ListForm(request.POST)
-        # TODO: here we need to take the value of the group (the group.id)
-        # and fetch the actual group to add to the DB
-        # but only if curation type is 'group' other wise the value of
-        # group is None
         if not form.is_valid():
             return redirect("lists")
         book_list = form.save()
@@ -208,6 +204,9 @@ class List(View):
         if not form.is_valid():
             return redirect("list", book_list.id)
         book_list = form.save()
+        if not book_list.curation == "group":
+            book_list.group = None
+            book_list.save()
         return redirect(book_list.local_path)