Remove nearby_place from the note model

Instead of storing the auto-generated meta information nearby_place
in the database, just look up the information on the fly when needed
and cache it for performance.

db/migrate/20121119165817_drop_nearby_place_from_notes.rb

@@ -0,0 +1,9 @@
+class DropNearbyPlaceFromNotes < ActiveRecord::Migration
+  def up
+    remove_column :notes, :nearby_place
+  end
+
+  def down
+    add_column :notes, :nearby_place, :string
+  end
+end