Media downloading indexing options (round 2) (#14)

* Adds options + option builder + metadata parsing for media thumbnails

* Added release-type options to media profile; built option parser for indexing operations

* Added new media_profile options to creation form; made show helper for rendering database items

* Added options for downloading/embedding metadata

* Adds option on sources to not download media (index only)

* reformatted docs

lib/pinchflat/media/media_item.ex

@@ -10,13 +10,23 @@ defmodule Pinchflat.Media.MediaItem do
   alias Pinchflat.MediaSource.Source
   alias Pinchflat.Media.MediaMetadata
 
+  @allowed_fields ~w(
+    title
+    media_id
+    media_filepath
+    source_id
+    subtitle_filepaths
+    thumbnail_filepath
+    metadata_filepath
+  )a
   @required_fields ~w(media_id source_id)a
-  @allowed_fields ~w(title media_id media_filepath source_id subtitle_filepaths)a
 
   schema "media_items" do
     field :title, :string
     field :media_id, :string
     field :media_filepath, :string
+    field :thumbnail_filepath, :string
+    field :metadata_filepath, :string
     # This is an array of [iso-2 language, filepath] pairs. Probably could
     # be an associated record, but I don't see the benefit right now.
     # Will very likely revisit because I can't leave well-enough alone.