Search images by file name (#206)

* feat(Images.Query): add literal file_name field

* feat(templates/search): add file_name to search dropdown

lib/philomena/images/query.ex

@@ -73,7 +73,7 @@ defmodule Philomena.Images.Query do
       float_fields: ~W(aspect_ratio wilson_score duration),
       date_fields: ~W(created_at updated_at first_seen_at),
       literal_fields:
-        ~W(faved_by orig_sha512_hash sha512_hash uploader source_url original_format mime_type),
+        ~W(faved_by orig_sha512_hash sha512_hash uploader source_url original_format mime_type file_name),
       bool_fields: ~W(animated processed thumbnails_generated),
       ngram_fields: ~W(description),
       custom_fields: ~W(gallery_id),

lib/philomena_web/templates/search/_form.html.slime

@@ -21,6 +21,7 @@ h1 Search
           a data-search-add="comment_count.gt:20" data-search-select-last="2" data-search-show-help="numeric" Number of comments
           a data-search-add="uploader:k_a" data-search-select-last="3" data-search-show-help="literal" Uploader
           a data-search-add="original_format:gif" data-search-select-last="3" data-search-show-help="literal" File extension
+          a data-search-add="file_name:tumblr_*" data-search-select-last="8" data-search-show-help="literal" Original file name
           a data-search-add="mime_type:image/jpeg" data-search-select-last="10" data-search-show-help="literal" MIME type
           a data-search-add="source_url:*deviantart.com*" data-search-select-last="16" data-search-show-help="literal" Image source URL
           a data-search-add="width:1920" data-search-select-last="4" data-search-show-help="numeric" Image width