discord: add /tagme command.

app/logical/deep_danbooru_client.rb

@@ -0,0 +1,28 @@
+class DeepDanbooruClient
+  attr_reader :http
+
+  def initialize(http: Danbooru::Http.new)
+    @http = http
+  end
+
+  def tags!(file)
+    html = post!("/upload", form: {
+      file: HTTP::FormData::File.new(file)
+    }).parse
+
+    tags = html.css("tbody tr").map do |row|
+      tag_name = row.css("td:first-child").text
+      confidence = row.css("td:last-child").text
+
+      # If tag_name is "rating:safe", then make a mock tag.
+      tag = Tag.find_by_name_or_alias(tag_name) || Tag.new(name: tag_name).freeze
+      [tag, confidence.to_f]
+    end.to_h
+
+    tags
+  end
+
+  def post!(url, **options)
+    http.post!("http://dev.kanotype.net:8003/deepdanbooru/#{url}", **options)
+  end
+end