diff --git a/Gemfile b/Gemfile
index b2d02c2d..7ab06201 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,7 +10,7 @@ if Gem::Version.new(Bundler::VERSION) < Gem::Version.new('1.8.4')
 end
 
 # as web framework
-gem 'rails', '~> 5.2.3'
+gem 'rails', '~> 5.2.4.3'
 
 # Use Puma as the app server
 gem 'puma', '~> 3.0'
@@ -118,7 +118,6 @@ gem 'bootstrap3-datetimepicker-rails', '~> 4.17.47'
 # data tables
 gem 'jquery-datatables'
 gem 'ajax-datatables-rails'
-# gem 'jquery-datatables-rails'
 
 # for charts
 gem 'chartkick'
diff --git a/Gemfile.lock b/Gemfile.lock
index 8fda9704..b4a25ecd 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -302,7 +302,7 @@ GEM
     nenv (0.3.0)
     netrc (0.11.0)
     nio4r (2.5.2)
-    nokogiri (1.10.9)
+    nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
     notiffany (0.1.1)
       nenv (~> 0.1)
@@ -591,7 +591,7 @@ GEM
       addressable (>= 2.3.6)
       crack (>= 0.3.2)
       hashdiff
-    websocket-driver (0.7.2)
+    websocket-driver (0.7.3)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
     whenever (0.10.0)
@@ -670,7 +670,7 @@ DEPENDENCIES
   prawn-qrcode
   prawn-rails
   puma (~> 3.0)
-  rails (~> 5.2.3)
+  rails (~> 5.2.4.3)
   rails-assets-bootstrap-markdown!
   rails-assets-bootstrap-select!
   rails-assets-date.format!
diff --git a/app/assets/stylesheets/application.css b/app/assets/stylesheets/application.css
index d6b84f1d..b0ae0823 100644
--- a/app/assets/stylesheets/application.css
+++ b/app/assets/stylesheets/application.css
@@ -1,11 +1,9 @@
 /*
- *= require dataTables/dataTables.bootstrap
- *= require datatables/extensions/Responsive/responsive.dataTables
- *= require dataTables/extensions/Responsive/responsive.bootstrap
- *= require dataTables/extensions/Select/select.bootstrap
+ *= require strap-on
+
+*= require dataTables/dataTables.bootstrap
  *= require dataTables/extensions/Buttons/buttons.dataTables
  *= require dataTables/extensions/Buttons/buttons.bootstrap
- *= require strap-on
  *= require formtastic-bootstrap
 
  *= require selectize