add geolocation search for public channels

db/migrate/20140804223739_add_geolocation_index_to_channels.rb

@@ -0,0 +1,6 @@
+class AddGeolocationIndexToChannels < ActiveRecord::Migration
+  def change
+    add_index :channels, [:latitude, :longitude]
+  end
+end
+

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20140801191621) do
+ActiveRecord::Schema.define(version: 20140804223739) do
 
   create_table "active_admin_comments", force: true do |t|
     t.string   "namespace"
@@ -107,6 +107,7 @@ ActiveRecord::Schema.define(version: 20140801191621) do
     t.text     "metadata"
   end
 
+  add_index "channels", ["latitude", "longitude"], name: "index_channels_on_latitude_and_longitude", using: :btree
   add_index "channels", ["public_flag", "last_entry_id", "updated_at"], name: "channels_public_viewable", using: :btree
   add_index "channels", ["ranking", "updated_at"], name: "index_channels_on_ranking_and_updated_at", using: :btree
   add_index "channels", ["realtime_io_serial_number"], name: "index_channels_on_realtime_io_serial_number", using: :btree