diff --git a/app/controllers/tags_controller.rb b/app/controllers/tags_controller.rb
index 35705a7e260bf618f28560c8329a8430ae3244d2..41548127745c026a200dbb2222f1cf895dee549a 100644
--- a/app/controllers/tags_controller.rb
+++ b/app/controllers/tags_controller.rb
@@ -31,8 +31,8 @@ class TagsController < ApplicationController
     @count = @tags.count
     table = params[:hierarchical].present? ? 'tags_paths' : 'tags'
     @tags = @tags.left_joins(:posts).group(Arel.sql("#{table}.id"))
-              .select(Arel.sql("#{table}.*, COUNT(posts.id) AS post_count"))
-              .paginate(per_page: 96, page: params[:page])
+                 .select(Arel.sql("#{table}.*, COUNT(posts.id) AS post_count"))
+                 .paginate(per_page: 96, page: params[:page])
   end
 
   def show
diff --git a/app/models/application_record.rb b/app/models/application_record.rb
index d65fc384a5a380c8f0fa52a2c32ad5556c222304..59bb7dbca76dfcf98ea7166ba5994eb139f0c959 100644
--- a/app/models/application_record.rb
+++ b/app/models/application_record.rb
@@ -43,11 +43,11 @@ class ApplicationRecord < ActiveRecord::Base
     return unless block_given?
 
     transaction do
-      connection.execute "SET @old_sql_mode = @@sql_mode"
+      connection.execute 'SET @old_sql_mode = @@sql_mode'
       connection.execute "SET SESSION sql_mode = REPLACE(REPLACE(@@sql_mode, 'ONLY_FULL_GROUP_BY,', ''), " \
                          "'ONLY_FULL_GROUP_BY', '')"
       yield
-      connection.execute "SET SESSION sql_mode = @old_sql_mode"
+      connection.execute 'SET SESSION sql_mode = @old_sql_mode'
     end
   end
 end
diff --git a/app/models/tag.rb b/app/models/tag.rb
index 51bf767f37e1eaf83d5382e7d29c049f0dd56f66..66a44621c8847513f47b4ad1527c9184d48edc5a 100644
--- a/app/models/tag.rb
+++ b/app/models/tag.rb
@@ -25,7 +25,7 @@ class Tag < ApplicationRecord
   def parent_chain
     Enumerator.new do |enum|
       parent_group = group
-      while parent_group != nil
+      until parent_group.nil?
         enum.yield parent_group
         parent_group = parent_group.group
       end
diff --git a/app/models/tag_with_path.rb b/app/models/tag_with_path.rb
index dde39913adf7e5a4c21ea562b3d8c941bf4d1de6..44df998e290e8253657a19b36d78a2d186aa7b95 100644
--- a/app/models/tag_with_path.rb
+++ b/app/models/tag_with_path.rb
@@ -1,3 +1,3 @@
 class TagWithPath < Tag
   self.table_name = 'tags_paths'
-end
\ No newline at end of file
+end