Fix MapLocation json_data to return mappable ids

Until we correctly make MapLocation relation with mappables a polymorphic
one... we'll need to return the investment_id and proposal_id values.

Right now it was returning the MapLocation ID, and the JS was making a
call searching for an Investment with the MapLocation ID... sometimes
finding a record with same ID but totally NOT the one associated to the
MapLocation.

app/assets/javascripts/map.js.coffee

@@ -99,7 +99,7 @@ App.Map =
       for i in addMarkerInvestments
         if App.Map.validCoordinates(i)
           marker = createMarker(i.lat, i.long)
-          marker.options['id'] = i.id
+          marker.options['id'] = i.investment_id
 
           marker.on 'click', openMarkerPopup
 

app/models/map_location.rb

@@ -11,7 +11,8 @@ class MapLocation < ActiveRecord::Base
 
   def json_data
     {
-      id: id,
+      investment_id: investment_id,
+      proposal_id: proposal_id,
       lat: latitude,
       long: longitude
     }