Merge pull request #17 from mjafshar/image_cache

Added subdirectory to story photos of businesses.
Created constants file
Updated .gitignore with the new api.rb file
Removed command to create subfolder in resources dir
  - The resources dir is read only so temp files cannot be cleared
Added method to create photo dir in documents dir.
updated write_image method with the new path
Updated business cell view to display images from the documents dir.