diff --git a/.rubocop.yml b/.rubocop.yml
index da0512c..4c9bfc2 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -11,6 +11,7 @@ AllCops:
     - 'db/schema.rb'
     - 'lib/tasks/cucumber.rake'
     - 'lib/templates/**/*'
+    - 'node_modules/**/*'
     - 'script/cucumber'
     - 'vendor/**/*'
 
diff --git a/.travis.yml b/.travis.yml
index 60eb4fa..3bc91f9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,6 +7,8 @@ services:
 
 env:
   global:
+    - RAILS_WEB_CONCURRENCY=1
+    - RAILS_MIN_THREADS=1
     - RAILS_MAX_THREADS=5
     - SIDEKIQ_CONCURRENCY=5
 
diff --git a/Gemfile b/Gemfile
index a30f20e..fce927f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,7 @@ ruby '2.7.0'
 
 source 'https://rubygems.org'
 
-git_source(:github) { |s| "https://github.com/#{s}.git" }
+git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
 gem 'aws-sdk-s3', require: false
 gem 'bcrypt', '~> 3.1'
@@ -28,7 +28,7 @@ gem 'puma', '~> 4.2'
 gem 'pundit', '~> 2.1'
 gem 'rack', '= 2.2.0', github: 'rack/rack'
 gem 'rack-attack', '~> 6.1'
-gem 'rails', '~> 6.0.0'
+gem 'rails', '~> 6.0.2', '~> 6.0.2.1'
 gem 'rails-i18n', '~> 6.0.0'
 gem 'recaptcha', '~> 5.1'
 gem 'redis', '~> 4.1'
diff --git a/Gemfile.lock b/Gemfile.lock
index a126f26..ff24f32 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -530,7 +530,7 @@ DEPENDENCIES
   pundit-matchers (~> 1.6)
   rack (= 2.2.0)!
   rack-attack (~> 6.1)
-  rails (~> 6.0.0)
+  rails (~> 6.0.2.1, ~> 6.0.2)
   rails-erd (~> 1.5)
   rails-i18n (~> 6.0.0)
   recaptcha (~> 5.1)
diff --git a/LICENSE b/LICENSE
index 86621c1..85510c9 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2018-2019 Alex Kotov
+Copyright (c) 2018-2020 Alex Kotov
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/config/application.rb b/config/application.rb
index 1da228a..192580d 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -4,13 +4,13 @@ require_relative 'boot'
 
 require 'rails'
 # Pick the frameworks you want:
-require 'active_model/railtie'
-require 'active_job/railtie'
-require 'active_record/railtie'
-require 'active_storage/engine'
 require 'action_controller/railtie'
 require 'action_mailer/railtie'
 require 'action_view/railtie'
+require 'active_job/railtie'
+require 'active_model/railtie'
+require 'active_record/railtie'
+require 'active_storage/engine'
 require 'sprockets/railtie'
 
 # Require the gems listed in Gemfile, including any gems
@@ -57,7 +57,8 @@ module Partynest
         config_for("settings/#{name}").deep_symbolize_keys.freeze
     end
 
-    # Initialize configuration defaults for originally generated Rails version.
+    # Initialize configuration defaults
+    # for originally generated Rails version.
     config.load_defaults 5.2
 
     # Custom directories with classes and modules you want to be autoloadable.
diff --git a/config/puma/development.rb b/config/puma/development.rb
index 7da0e5b..ecc8a2c 100644
--- a/config/puma/development.rb
+++ b/config/puma/development.rb
@@ -2,8 +2,10 @@
 
 root_dir = File.expand_path '../..', __dir__
 
-workers_count = ENV.fetch('WEB_CONCURRENCY') { 1 }
-threads_count = ENV.fetch('RAILS_MAX_THREADS') { 5 }
+workers_count     = ENV.fetch('RAILS_WEB_CONCURRENCY') { 1 }
+max_threads_count = ENV.fetch('RAILS_MAX_THREADS') { 5 }
+min_threads_count = ENV.fetch('RAILS_MIN_THREADS') { max_threads_count }
+port_number       = ENV.fetch('PORT') { 3000 }
 
 # Specifies the number of `workers` to boot in clustered mode.
 # Workers are forked webserver processes. If using threads and workers together
@@ -19,7 +21,7 @@ workers workers_count
 # the maximum value specified for Puma. Default is set to 5 threads for minimum
 # and maximum; this matches the default thread size of Active Record.
 #
-threads threads_count, threads_count
+threads min_threads_count, max_threads_count
 
 # Use the `preload_app!` method when specifying a `workers` number.
 # This directive tells Puma to first boot the application and load code
@@ -31,7 +33,7 @@ threads threads_count, threads_count
 # Specifies the `port` that Puma will listen on to receive requests;
 # default is 3000.
 #
-port ENV.fetch('PORT') { 3000 }
+port port_number
 
 # Allow puma to be restarted by `rails restart` command.
 plugin :tmp_restart
diff --git a/config/puma/production.rb b/config/puma/production.rb
index 32c02be..be1ddc2 100644
--- a/config/puma/production.rb
+++ b/config/puma/production.rb
@@ -2,8 +2,9 @@
 
 root_dir = File.expand_path '../..', __dir__
 
-workers_count = ENV.fetch('WEB_CONCURRENCY') { 1 }
-threads_count = ENV.fetch('RAILS_MAX_THREADS') { 5 }
+workers_count     = ENV.fetch('RAILS_WEB_CONCURRENCY') { 1 }
+max_threads_count = ENV.fetch('RAILS_MAX_THREADS') { 5 }
+min_threads_count = ENV.fetch('RAILS_MIN_THREADS') { max_threads_count }
 
 # Specifies the number of `workers` to boot in clustered mode.
 # Workers are forked webserver processes. If using threads and workers together
@@ -19,7 +20,7 @@ workers workers_count
 # the maximum value specified for Puma. Default is set to 5 threads for minimum
 # and maximum; this matches the default thread size of Active Record.
 #
-threads threads_count, threads_count
+threads min_threads_count, max_threads_count
 
 # Use the `preload_app!` method when specifying a `workers` number.
 # This directive tells Puma to first boot the application and load code
@@ -33,9 +34,6 @@ threads threads_count, threads_count
 #
 bind "unix://#{File.join(root_dir, 'tmp', 'sockets', 'puma.sock')}"
 
-# Allow puma to be restarted by `rails restart` command.
-# plugin :tmp_restart
-
 # Use "path" as the file to store the server info state. This is
 # used by "pumactl" to query and control the server.
 #
diff --git a/config/puma/staging.rb b/config/puma/staging.rb
index 32c02be..be1ddc2 100644
--- a/config/puma/staging.rb
+++ b/config/puma/staging.rb
@@ -2,8 +2,9 @@
 
 root_dir = File.expand_path '../..', __dir__
 
-workers_count = ENV.fetch('WEB_CONCURRENCY') { 1 }
-threads_count = ENV.fetch('RAILS_MAX_THREADS') { 5 }
+workers_count     = ENV.fetch('RAILS_WEB_CONCURRENCY') { 1 }
+max_threads_count = ENV.fetch('RAILS_MAX_THREADS') { 5 }
+min_threads_count = ENV.fetch('RAILS_MIN_THREADS') { max_threads_count }
 
 # Specifies the number of `workers` to boot in clustered mode.
 # Workers are forked webserver processes. If using threads and workers together
@@ -19,7 +20,7 @@ workers workers_count
 # the maximum value specified for Puma. Default is set to 5 threads for minimum
 # and maximum; this matches the default thread size of Active Record.
 #
-threads threads_count, threads_count
+threads min_threads_count, max_threads_count
 
 # Use the `preload_app!` method when specifying a `workers` number.
 # This directive tells Puma to first boot the application and load code
@@ -33,9 +34,6 @@ threads threads_count, threads_count
 #
 bind "unix://#{File.join(root_dir, 'tmp', 'sockets', 'puma.sock')}"
 
-# Allow puma to be restarted by `rails restart` command.
-# plugin :tmp_restart
-
 # Use "path" as the file to store the server info state. This is
 # used by "pumactl" to query and control the server.
 #
diff --git a/config/spring.rb b/config/spring.rb
index c5933e4..c31fc59 100644
--- a/config/spring.rb
+++ b/config/spring.rb
@@ -1,8 +1,9 @@
 # frozen_string_literal: true
 
-%w[
-  .ruby-version
-  .rbenv-vars
-  tmp/restart.txt
-  tmp/caching-dev.txt
-].each { |path| Spring.watch(path) }
+Spring.watch(
+  '.ruby-version',
+  '.ruby-gemset',
+  '.rbenv-vars',
+  'tmp/restart.txt',
+  'tmp/caching-dev.txt',
+)
diff --git a/config/storage.yml b/config/storage.yml
index 5ccd70d..de3a961 100644
--- a/config/storage.yml
+++ b/config/storage.yml
@@ -1,6 +1,6 @@
 test:
   service: Disk
-  root: <%= Rails.root.join 'tmp', 'storage' %>
+  root: <%= Rails.root.join 'tmp/storage' %>
 
 local:
   service: Disk
diff --git a/db/seeds.rb b/db/seeds.rb
index 8622cd9..57e14a8 100644
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -4,7 +4,7 @@ require 'csv'
 
 def csv_foreach(filename, &block)
   CSV.foreach(
-    Rails.root.join('db', 'data', "#{filename}.csv"),
+    Rails.root.join("db/data/#{filename}.csv"),
     col_sep: '|',
     &block
   )