conform to rubocop

app/controllers/posts_controller.rb

@@ -45,7 +45,7 @@ class PostsController < ApplicationController
     gflash error: 'Gmail authentication expired.'
     redirect_to root_path(id: @post.id)
   rescue ArgumentError => err
-    gflash error: "Mail format is invalid: #{err.to_s}"
+    gflash error: "Mail format is invalid: #{err}"
     redirect_to root_path(id: @post.id)
   end
 

app/controllers/tags_controller.rb

@@ -60,7 +60,7 @@ class TagsController < ApplicationController
     @tag.move_all_posts_to!(@merge_to_tag)
     @tag.delete
 
-   gflash success: "「#{@tag.name}」は「#{@merge_to_tag.name}」にmergeされました"
+    gflash success: "「#{@tag.name}」は「#{@merge_to_tag.name}」にmergeされました"
 
     render json: { status: 'OK' }
   end

app/models/post.rb

@@ -91,13 +91,13 @@ class Post < ActiveRecord::Base
   # Class method
   ######################################################################
   def self.most_pv_in_this_week(limit)
-    posts_with_footprints = where(arel_table[:created_at].gt 1.week.ago).
-      select("posts.id, count(footprints.id) AS footprints_count").
-      joins(:footprints).
-      group("posts.id").
-      order("footprints_count DESC").
-      limit(limit)
-    posts = self.find(posts_with_footprints.map(&:id))
+    posts_with_footprints = where(arel_table[:created_at].gt 1.week.ago)
+                            .select('posts.id, count(footprints.id) AS footprints_count')
+                            .joins(:footprints)
+                            .group('posts.id')
+                            .order('footprints_count DESC')
+                            .limit(limit)
+    posts = find(posts_with_footprints.map(&:id))
     posts.to_a.zip posts_with_footprints.map(&:footprints_count)
   end
 

app/models/user.rb

@@ -58,7 +58,6 @@ class User < ActiveRecord::Base
 
   scope :now_viewing, -> { joins(:footprints).where('footprints.updated_at > ?', 10.minutes.ago) }
 
-
   ######################################################################
   # Validations
   ######################################################################