Creating GeoJson

map.js

function drawIndexReportMap(){
  L.mapbox.accessToken = "YOUR_TOKEN";

  var map = L.mapbox.map("map", "lizvdk.knp8dn4m", { zoomControl: false }):
  
  var featureLayer = L.mapbox.featureLayer().addTo(map);

  featureLayer.on('layeradd', function (e) {
    featureLayer.eachLayer(function(layer) {
      var marker = e.layer,
      feature = marker.feature;
      marker.setIcon(L.divIcon(feature.properties.icon));
    });
  });

  featureLayer.loadURL('/reports.json');

  map.featureLayer.on('ready', function(e) {
    featureLayer.eachLayer(function(layer) {
      item.onclick = function() {
        map.setView(layer.getLatLng(), 19);
        layer.openPopup();
      };
      var content =
                    '<a target="_blank" class="popup" href="' +
                      layer.feature.properties.url + '">' +
                      '<img class="th radius" src="' +
                        layer.feature.properties.photo +
                      '" />' +
                      layer.feature.properties.category +
                      '</a>';
      layer.bindPopup(content, { minWidth: 300 });
    });
  });
}

report.rb

class Report < ActiveRecord::Base
  def self.geojson
    geojson = Hash.new
    features = []
    geojson[:type] = "FeatureCollection"
    geojson[:features] = features
    by_recency.each do |report|
      features << {
        type: "Feature",
        geometry: {
          type: "Point",
          coordinates: [report.longitude, report.latitude]
        },
        properties: {
          category: report.category.name,
          url: "/reports/#{report.id}",
          photo: report.photo.url,
          updated_at: report.display_date,
          id: "report-#{report.id}",
          icon: {
            html: report.category.icon,
            iconSize: [50, 50],
            iconAnchor: [25, 25],
            popupAnchor: [0, -25],
            className: "#{report.marker_color} map-icon"
          }
        }
      }
    end
    geojson
  end
end

reports_controller.rb

class ReportsController < ApplicationController
  def index
    @reports = Report.by_recency
    @geojson = Report.geojson

    respond_to do |format|
     format.html
     format.json { render json: @geojson }
    end
  end
end