Based on Spree Delivery Time.
It allows admins to define time ranges for orders delivery instead of let users define it by themselves like on spree_delivery_time.
The users can select a range of time, defined by the admin, during the checkout process to chose when they want to receive their order.
Add this line to your application's Gemfile:
gem 'spree_delivery_time_range'
And then execute:
$ bundle
Or install it yourself as:
$ gem install spree_delivery_time_range
$ rails g spree_delivery_time_range:install
to install and run the migrations. This migration simply adds delivery_time column to Spree::Order and a new table to persist time ranges defined by the admin.
Code improvements are welcome!