Merge pull request #5 from sammy/edit_item

Edit item
implemented slugs for items
Merge pull request #6 from sammy/item_slugs

Item slugs
fixed failed item tests after implementing slugs
implemented item deletion
finished tests for delete action
added one more edge case to deletion of items
Merge pull request #7 from sammy/destroy_items

Destroy items
fixed error in group population in edit form, it was bringing all groups instead of the logged in users groups
added a link to the items title in the index page of items
resolved conflicts