Google maps add listener to marker

I want to add event listener to all markers, i'm using Google-Maps-for-Rails gem. This is my code

  markers_from_api = data.bookings
  handler = Gmaps.build('Google')
  settings = {
    internal: {
      id: 'multi_markers'
    },
    provider:{
      styles: mapStyles
    }
  }
  handler.buildMap settings, ->
    markers = handler.addMarkers(markers_from_api)
    _.each markers,(i, j) ->
      google.maps.event.addListener i, 'click', (object) ->
        alert 'hello'
        return
    createSidebar markers_from_api
    createSidebarLi markers_from_api
    handler.bounds.extendWith markers
    handler.fitMapToBounds()

I tried to add event listener to all marker but it doesnt alert anything. How can i add event listeners in google maps for rails

I have an array of data, where each data contain id, lat, lng