Shopping Items - Add new Items

[alemputes]

As a User, I want to add new items to my shopping lists.

Note: Item most be associated with the specific list.

• [x] Create in toolbar a entry cell and button to add new item
• [ ] If added, post it to the API
• [x] Display in UI

[alemputes]

Needs the API to update the Add implementation then it's to be done.