Grid:

class UsersGrid < BaseGrid

  #
  # Scope
  #

  scope do
    User
  end

  #
  # Filters
  #

  filter(:id, :string, multiple: ',')
  filter(:email, :string)
  filter(:disabled, :xboolean)
  filter(:registration_type, :enum, select: User::REGISTRATION_TYPES.map {|r| [r.humanize, r]})
  filter(
    :logins_count, :integer,
    range: true,
    default: proc { [User.minimum(:logins_count), User.maximum(:logins_count)]},
    input_options: {type: 'number'},
  )
  filter(:registered_at, :date, range: true, input_options: {type: 'date'})
  filter(:condition, :dynamic, header: "Dynamic condition")
  column_names_filter(header: "Extra Columns", checkboxes: true)

  #
  # Columns
  #

  column(:id, mandatory: true)
  column(:email, mandatory: true) do |model|
    format(model.email) do |value|
      link_to value, "mailto:#{value}"
    end
  end
  column(:name, mandatory: true)
  column(:disabled, mandatory: true) do
    disabled? ? "Yes" : "No"
  end

  column(:registration_type) do |record|
    record.registration_type.humanize
  end
  column(:logins_count)
  column(:registered_at) do |record|
    record.registered_at.to_date
  end
  column(:age, header: "Registration Age") do |record|
    age = (DateTime.now.in_time_zone - record.registered_at) / 1.day
    "#{age.to_i} days"
  end

  column(:actions, html: true, mandatory: true) do |record|
    link_to "Delete", "javascript:alert('Oh common! This is a demo.')"
  end
end

Controller:

class UsersController < ApplicationController

  def index
    @users_grid = UsersGrid.new(params[:g]) do |scope|
      scope.page(params[:page])
    end
  end
end

View:

 <h3>Users Grid</h3>

<div class="right">
  <%= render :partial => "shared/source", :object => @users_grid %>
</div>
<div class="left">
  <%= datagrid_form_for @users_grid, url: users_path %>


  <div class='total'>Total: <%= @users_grid.assets.total_count %></div>
  <%= datagrid_table(@users_grid) %>
  <%= paginate @users_grid.assets %>
</div>