add user similarity report

app/presenters/user_similarity_presenter.rb

@@ -0,0 +1,34 @@
+class UserSimilarityPresenter
+  attr_reader :report, :not_ready
+
+  def initialize(report)
+    @report = report
+    fetch
+  end
+
+  def not_ready?
+    not_ready
+  end
+
+  def insufficient_data?
+    report.user.favorite_count < 500
+  end
+
+  def fetch
+    user_ids = report.fetch_similar_user_ids
+
+    if user_ids = "not ready"
+      @not_ready = true
+    else
+      @user_ids = user_ids.scan(/\d+/).slice(0, 10)
+    end
+  end
+
+  def each_user(&block)
+    User.where(id: user_ids).each(&block)
+  end
+
+  def each_favorite_for(user, &block)
+    user.favorites.limit(6).joins(:post).reorder("favorites.id desc").map(&:post).each(&block)
+  end
+end