TIL, 2017-08-07

dependent: :destroy
Searching and filtering: construct the where clause in the query builder part of the code.
lol_dba: Gem to find which columns should be indexed.
is_defined?
Rails.application.eager_load! – loads all railties.
ObjectSpace.each_object(Module): gets all currently loaded objects.
Pomodoro.descends_from_active_record? is a thing.
Pomodoro.reflections to see the has_many, etc. relationships.
ActiveSupport#each_pair: Calls block once for each key, passing the key-value as parameters.
ActiveRecord::Base.indexes('books') to list all the indices.
Don’t put things in the app directory that you don’t want to load anyway.
FileUtils.rm_rf
The where method in AR returns a proxy object.