activerecord.rb

# Notes on ActiveRecord methods and idioms

# Raises an exception if there is a problem
Model.create!(attrs)

# Returns true or false (no exceptions are raised)
Model.create(attrs)

ruby.rb

# the !! forces a return of true or false even if nil
def give_me_boolean_or_give_me_death(foo)
  !!foo
end

# >> give_me_boolean_or_give_me_death nil
# => false
# >> give_me_boolean_or_give_me_death true
# => true