Clean up redis configuration. Allow using REDIS_URL to set advanced (#2732)

connection options instead of setting REDIS_HOST etc individually

Close #1986

config/environments/production.rb

@@ -45,27 +45,6 @@ Rails.application.configure do
   # Use a different logger for distributed setups.
   # config.logger = ActiveSupport::TaggedLogging.new(SyslogLogger.new)
 
-  # Parse and split the REDIS_URL if passed (used with hosting platforms such as Heroku).
-  # Set ENV variables because they are used elsewhere.
-  if ENV['REDIS_URL']
-    redis_url = URI.parse(ENV['REDIS_URL'])
-    ENV['REDIS_HOST'] = redis_url.host
-    ENV['REDIS_PORT'] = redis_url.port.to_s
-    ENV['REDIS_PASSWORD'] = redis_url.password
-    db_num = redis_url.path[1..-1]
-    ENV['REDIS_DB'] = db_num if db_num.present?
-  end
-
-  # Use a different cache store in production.
-  config.cache_store = :redis_store, {
-    host: ENV.fetch('REDIS_HOST') { 'localhost' },
-    port: ENV.fetch('REDIS_PORT') { 6379 },
-    password: ENV.fetch('REDIS_PASSWORD') { false },
-    db: ENV.fetch('REDIS_DB') { 0 },
-    namespace: 'cache',
-    expires_in: 10.minutes,
-  }
-
   # Enable serving of images, stylesheets, and JavaScripts from an asset server.
   # config.action_controller.asset_host = 'http://assets.example.com'