Turn Group acronym into a SlugField, make the admin prepopulate the acronym

- Legacy-Id: 4012

ietf/group/admin.py

@@ -25,6 +25,7 @@ class GroupAdmin(admin.ModelAdmin):
     ordering = ["name"]
     raw_id_fields = ["charter", "parent", "ad"]
     inlines = [RoleInline]
+    prepopulated_fields = {"acronym": ("name", )}
 
     def role_list(self, obj):
         roles = Role.objects.filter(group=obj).order_by("name", "person__name").select_related('person')

ietf/group/models.py

@@ -34,7 +34,7 @@ class GroupManager(models.Manager):
 class Group(GroupInfo):
     objects = GroupManager()
 
-    acronym = models.CharField(max_length=40, unique=True, db_index=True)
+    acronym = models.SlugField(max_length=40, unique=True, db_index=True)
     charter = models.OneToOneField('doc.Document', related_name='chartered_group', blank=True, null=True)
     
     def latest_event(self, *args, **filter_args):