update docs for API keys

app/controllers/charts_controller.rb

@@ -38,7 +38,7 @@ class ChartsController < ApplicationController
   def show
 
     # allow these parameters when creating feed querystring
-    feed_params = ['key','days','start','end','round','timescale','average','median','sum','results','location','status']
+    feed_params = ['key', 'api_key', 'apikey', 'days','start','end','round','timescale','average','median','sum','results','location','status']
 
     # set chart size
     width = params[:width].present? ? params[:width] : Chart.default_width