additions api api-blueprint apib apis b-tree beam binaries builder caching class cli codes command-line constant conventions cookies copy cowboy csv data-structures decorators double dummy endpoint exceptions expressiveness extract factory fake filtering first-principles floats formatters gem gemfile genserver getting-started git golang hateoas haveibeenpwned hexpm history hoisting hsts http humble idempotency json last-recently-used launchagent launchctl launchd lfu library linked-lists lists logging lpc lru method methods middleware migrate minitest mixins mock mson object parameters params passwords pattern patterns pending plugin pov precision presenters primitive-obsession priority-queues processes provider queues rack rake redis router rspec service services signals singleton skopje smelly stacks startup status strategy stripe stub taken tdd template template-method test testing trees url-shortener value videos weather weekend widget