Bump rails to 5.2 and update rubocop

config/initializers/active_admin.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 ActiveAdmin.setup do |config|
   # == Site Title
   #

config/initializers/application_controller_renderer.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 # Be sure to restart your server when you modify this file.
 
 # ActiveSupport::Reloader.to_prepare do

config/initializers/assets.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 # Version of your assets, change this if you want to expire all your assets.

config/initializers/backtrace_silencers.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 # Be sure to restart your server when you modify this file.
 
 # You can add backtrace silencers for libraries that you're using but don't wish to see in your backtraces.

config/initializers/content_security_policy.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+# Be sure to restart your server when you modify this file.
+
+# Define an application-wide content security policy
+# For further information see the following documentation
+# https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
+
+# Rails.application.config.content_security_policy do |policy|
+#   policy.default_src :self, :https
+#   policy.font_src    :self, :https, :data
+#   policy.img_src     :self, :https, :data
+#   policy.object_src  :none
+#   policy.script_src  :self, :https
+#   policy.style_src   :self, :https
+
+#   # Specify URI for violation reports
+#   # policy.report_uri "/csp-violation-report-endpoint"
+# end
+
+# If you are using UJS then enable automatic nonce generation
+# Rails.application.config.content_security_policy_nonce_generator = -> request { SecureRandom.base64(16) }
+
+# Report CSP violations to a specified URI
+# For further information see the following documentation:
+# https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy-Report-Only
+# Rails.application.config.content_security_policy_report_only = true

config/initializers/cookies_serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 # Specify a serializer for the signed and encrypted cookie jars.

config/initializers/filter_parameter_logging.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 # Configure sensitive parameters which will be filtered from the log file.

config/initializers/inflections.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 # Be sure to restart your server when you modify this file.
 
 # Add new inflection rules using the following format. Inflections

config/initializers/mime_types.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 # Be sure to restart your server when you modify this file.
 
 # Add new mime types for use in respond_to blocks:

config/initializers/new_framework_defaults_5_2.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+# Be sure to restart your server when you modify this file.
+#
+# This file contains migration options to ease your Rails 5.2 upgrade.
+#
+# Once upgraded flip defaults one by one to migrate to the new default.
+#
+# Read the Guide for Upgrading Ruby on Rails for more info on each option.
+
+# Make Active Record use stable #cache_key alongside new #cache_version method.
+# This is needed for recyclable cache keys.
+# Rails.application.config.active_record.cache_versioning = true
+
+# Use AES-256-GCM authenticated encryption for encrypted cookies.
+# Also, embed cookie expiry in signed or encrypted cookies for increased security.
+#
+# This option is not backwards compatible with earlier Rails versions.
+# It's best enabled when your entire app is migrated and stable on 5.2.
+#
+# Existing cookies will be converted on read then written with the new scheme.
+# Rails.application.config.action_dispatch.use_authenticated_cookie_encryption = true
+
+# Use AES-256-GCM authenticated encryption as default cipher for encrypting messages
+# instead of AES-256-CBC, when use_authenticated_message_encryption is set to true.
+# Rails.application.config.active_support.use_authenticated_message_encryption = true
+
+# Add default protection from forgery to ActionController::Base instead of in
+# ApplicationController.
+# Rails.application.config.action_controller.default_protect_from_forgery = true
+
+# Store boolean values are in sqlite3 databases as 1 and 0 instead of 't' and
+# 'f' after migrating old data.
+# Rails.application.config.active_record.sqlite3.represent_boolean_as_integer = true
+
+# Use SHA-1 instead of MD5 to generate non-sensitive digests, such as the ETag header.
+# Rails.application.config.active_support.use_sha1_digests = true
+
+# Make `form_with` generate id attributes for any generated HTML tags.
+# Rails.application.config.action_view.form_with_generates_ids = true

config/initializers/wrap_parameters.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 # This file contains settings for ActionController::ParamsWrapper which