map.html.erb

<%= gmaps({
    "map_options" => { "type" => "ROADMAP", "center_longitude" => 180, "zoom" => 3, "auto_adjust" => true},
    "markers"     => {
		"data" => json_array(@posts).to_json
	}
}) %>

posts_helper.rb

module PostsHelper

 def json_array(posts)
      posts.map do |post|
      hash = {
             "description" => "#{post.title}<br />#{post.company}<br />", 
             "title" => "", 
             "width" => "",
             "height" => "",
             "lng" => post.longitude.to_s(),
             "lat" => post.latitude.to_s(),
            }
       hash
    end
  end

end