added dates created/modified to crops csv

app/controllers/crops_controller.rb

@@ -14,8 +14,8 @@ class CropsController < ApplicationController
       format.json { render :json => @crops }
       format.rss { render :layout => false }
       format.csv do
-        @filename = "Growstuff-Crops-#{Time.zone.now.to_s(:number)}"
-        @crops = Crop.all
+        @filename = "Growstuff-Crops-#{Time.zone.now.to_s(:number)}.csv"
+        @crops = Crop.includes(:scientific_names, :plantings, :seeds)
         render :csv => @crops
       end
     end

app/views/crops/index.csv.shaper

@@ -19,7 +19,9 @@ csv.headers :id, :system_name,
   :planted_from_bare_root_plant,
   :planted_from_advanced_plant,
   :planted_from_graft,
-  :planted_from_layering
+  :planted_from_layering,
+  :date_added,
+  :last_modified
 
 @crops.each do |c|
   csv.row c do |csv, crop|
@@ -65,5 +67,8 @@ csv.headers :id, :system_name,
     csv.cell :planted_from_graft, planted_from['graft']
     csv.cell :planted_from_layering, planted_from['layering']
 
+    csv.cell :date_added, c.created_at.to_s(:db)
+    csv.cell :last_modified, c.updated_at.to_s(:db)
+
   end
 end