Groups Members all API fix

groups/:id/members/all would not return users of groups invited to the
current group.
Added relation to seek for users from :shared_with_groups within
current_group, similar to how projects do it in project_invited_groups
of member_finder.rb.
Changelog: fixed
Signed-off-by: Lucas Zampieri <lzampier@redhat.com>

app/finders/group_members_finder.rb

@@ -58,6 +58,8 @@ class GroupMembersFinder < UnionFinder
       find_union([group.ancestors, group.descendants], Group)
     when [:descendants, :direct, :inherited]
       group.self_and_hierarchy
+    when [:direct, :inherited, :shared_with_groups]
+      find_union([group.self_and_ancestors, group.shared_with_groups], Group)
     else
       nil
     end

lib/api/helpers/members_helpers.rb

@@ -50,7 +50,7 @@ module API
       end
 
       def find_all_members_for_group(group)
-        GroupMembersFinder.new(group).execute
+        GroupMembersFinder.new(group).execute(include_relations: [:inherited, :direct, :shared_with_groups])
       end
 
       def present_members(members)