Decouple Queue and related classes from MangaDex

src/plugin/downloader.cr

@@ -0,0 +1,18 @@
+class Plugin
+  class Downloader < Queue::Downloader
+    @library_path : String = Config.current.library_path
+    @downloading = false
+
+    def self.default : self
+      unless @@default
+        @@default = new
+      end
+      @@default.not_nil!
+    end
+
+    def initialize
+      @queue = Queue.default
+      @queue << self
+    end
+  end
+end