A complete guide to ORMs and database libraries in Ruby — comparing ActiveRecord, Sequel, ROM (Ruby Object Mapper), Hanami::Model, DataMapper, Ohm for Redis, Mongoid for MongoDB, the Repository Pattern, Query Objects, clean persistence architecture, choosing the right ORM for each situation, and migrating between ORMs.
A complete guide to Selenium WebDriver in Ruby — installing selenium-webdriver, managing drivers with the webdrivers gem, browser navigation, finding elements with various locator strategies, click and input actions, waiting for elements with explicit and implicit waits, screenshots, JavaScript execution, frames and windows, Capybara with RSpec for integration testing, the Page Object Model, headless browsers, and a Selenium vs Capybara vs Ferrum comparison.