How do I fetch all the markers with Google Maps for Rails - gmaps4rails

Question

I am using the Google Maps for Rails gem by appneadiving and would like to add listeners to already existing markers. I wanted to know how to fetch all the markers, I tried looking through the source code but could not figure it out yet.
I'm using version 2.1.2 with Rails 3.2.14. Although my original question was about grabbing all the markers it may not be necessary given what I need to do.
I probably should have went with a name other than session but in my app session refers to activity session. Each marker represents an activity taking place at that location and I just want information about that activity to be displayed if you hover over the marker. I also want a button to join the activity below the info so it would be a form. I already have a form for creating an activity/marker at any location that is clicked but don't know how I would add callbacks to events on the marker. It's a single page app and this the code for root.html.erb, the root page.
<script src="//maps.google.com/maps/api/js?v=3.13&sensor=false&libraries=geometry" type="text/javascript"></script>
<script src='//google-maps-utility-library-v3.googlecode.com/svn/tags/markerclustererplus/2.0.14/src/markerclusterer_packed.js' type='text/javascript'></script>
<script src='//google-maps-utility-library-v3.googlecode.com/svn/tags/infobox/1.1.5/src/infobox.js'></script>
<script type="application/json" id="bootstrapped_sessions_json">
{ "sessions": <%= Session.all.to_json.html_safe %> }
</script>
<div class="container" style='padding-top: 60px'>
<div class="row">
<div class="span8">
<div style='width: 800px;'>
<div id="map" style='width: 800px; height: 400px;'></div>
</div>
</div>
<div class="span4">
<div style="padding-left:10px;">
Closest users/sessions
</div>
</div>
</div>
</div>
<script type='text/template' id='create_session_template'>
<form action='<%= api_sessions_url %>' method='POST'>
<label for='activity_name'>Activity</label>
<input type='text' name='session[activity]' id='activity_name'>
<label for='end_time'>End Time</label>
<input type='time' name='session[end_time]'>
<input type='hidden' name='session[latitude]' value='<%%= lat %>'>
<input type='hidden' name='session[longitude]' value='<%%= lng %>'>
<input type='hidden' name='session[size]' value='1'>
<input type='hidden' name='authenticity_token' value='<%= form_authenticity_token %>'>
<input type='submit' value='Broadcast Interest'>
</form>
</script>
<script type="text/javascript">
var initialize = function() {
var data = JSON.parse($("#bootstrapped_sessions_json").html())
var markerCoordinates = data['sessions'].map(function (coord) {
return {lat: coord["latitude"], lng: coord["longitude"]}
});
var handler = Gmaps.build('Google');
handler.buildMap({ provider: { minZoom: 1 }, internal: {id: 'map'}}, function() {
var markers = handler.addMarkers(markerCoordinates);
handler.bounds.extendWith(markers);
handler.fitMapToBounds();
handler.map.centerOn({ lat: 40.7356, lng: -73.9906 })
google.maps.event.addListener(handler.getMap(), 'click', function (e) {
console.log(e.latLng)
var lat = e.latLng.ob
var lng = e.latLng.pb
renderSessionForm({'lat': lat, 'lng': lng, 'map': handler.getMap()});
});
});
};
var renderSessionForm = function (options) {
var lat = options['lat'];
var lng = options['lng'];
var map = options['map'];
var boxText = document.createElement("div");
boxText.style.cssText = "border: 1px solid black; margin-top: 8px; background: black; padding: 5px;";
var myOptions = {
content: boxText
,disableAutoPan: false
,maxWidth: 0
,pixelOffset: new google.maps.Size(-140, 0)
,zIndex: null
,boxStyle: {
background: "url('tipbox.gif') no-repeat"
,opacity: 1
,width: "280px"
}
,closeBoxMargin: "10px 2px 2px 2px"
,closeBoxURL: "http://www.google.com/intl/en_us/mapfiles/close.gif"
,infoBoxClearance: new google.maps.Size(1, 1)
,isHidden: false
,pane: "floatPane"
,enableEventPropagation: false
};
var ib = new InfoBox(myOptions);
var templateCode = $('#create_session_template').html();
var templateFn = _.template(templateCode);
boxText.innerHTML = templateFn({'lat': lat, 'lng': lng})
ib.open(map);
}
window.onload = initialize();
</script>