Minidusen: Filtering associated records

Minidusen lets you find text in associated records.

Assume the following model where a Contact record may be associated with a Group record:

class Contact < ApplicationRecord
  belongs_to :group

  validates_presence_of :name, :street, :city, :email
end

class Group < ApplicationRecord
  has_many :contacts

  validates_presence_of :name
end

We can filter contacts by their group name by joining the groups table and filtering on a joined column.
Note how the joined column is qualified as groups.name (rather than just name):

class ContactFilter
  include Minidusen::Filter

  filter :text do |scope, phrases|
    columns = [:name, :email, 'groups.name']
    scope.joins(:group).where_like(columns => phrases)
  end
end