Missing documentation items for Symfony migration

Here's a list of things we need to document (the list will evolve in time)

Related to Grid

• How to use reusable Javascript grid Extensions https://github.com/PrestaShop/docs/pull/240
• How to add bulk actions to a grid https://github.com/PrestaShop/docs/pull/244
• How link actions work (see https://github.com/PrestaShop/docs/pull/244#issuecomment-482580858)

Related to Symfony (focus on controller / app layer of the migration)

• Reusable PrestaShop form types
• PrestaShop console commands
• How to create a new page / controller (step-by-step tutorial), listing and CRUD
• How to use composition and SF services to extend PrestaShop behavior
• Overview of the main services being used in PrestaShop
• Twig folder structure and usage
• Prestashop twigs macros and UI-Kit usage
• Thin controller, fat models
• Internal usage of roles for PrestaShop, linked with security
• About Identifiable Objects forms https://github.com/PrestaShop/docs/pull/184
• Improve "settings form" doc (see https://github.com/PrestaShop/docs/pull/184#issuecomment-481714552)
• Reusable PrestaShop form types https://github.com/PrestaShop/docs/pull/245

Related to CQRS (focus on domain / core layer of the migration)

• What is CQRS https://github.com/PrestaShop/docs/pull/232
• Focus on CQRS being used by PrestaShop: legacy handlers layer
• Use of ValueObjects and DTOs (related to CQRS)
• Using Domain Exceptions and how to handle them https://github.com/PrestaShop/docs/pull/255
• What is the usage of Adapter namespace and its content

Related to new Admin Theme

• A zoom on how we use webpack
• Using scss

Related to testing

• Writing unit tests
• Writing behat tests
• Writing puppeeter tests (soon)