refact

lib/service/message_service.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class MessageService
+  def initialize(repo) = @repo = repo
+
+  def recent(count = 30) = @repo.last(count)
+  def count              = @repo.count
+
+  def post(username, text)
+    return :empty if text.strip.empty?
+    @repo.append(username, text.strip[0...200])
+    :ok
+  end
+end