Healthcheck added

https://github.com/linqueta/rails-healthcheck

config/initializers/healthcheck.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+Healthcheck.configure do |config|
+  config.success = 200
+  config.error = 503
+  config.verbose = false
+  config.route = '/healthcheck'
+  config.method = :get
+
+  # -- Custom Response --
+  # config.custom = lambda { |controller, checker|
+  #   controller.render json: my_custom_response unless checker.errored?
+  #   ...
+  # }
+
+  # -- Checks --
+  # config.add_check :database,     -> { ActiveRecord::Base.connection.execute('select 1') }
+  # config.add_check :migrations,   -> { ActiveRecord::Migration.check_pending! }
+  # config.add_check :cache,        -> { Rails.cache.read('some_key') }
+  # config.add_check :environments, -> { Dotenv.require_keys('ENV_NAME', 'ANOTHER_ENV') }
+end

config/routes.rb

@@ -1,5 +1,6 @@
 Rails.application.routes.draw do
 
+  Healthcheck.routes(self)
   get 'admin/status'
 
   get 'admin/screenshots'