Sidekiq error: could not connect to server: No such file or directory

问题

I am having trouble with my sidekiq, heroku, redistogo, rails 4 configuration. I have 1 dyno and 1 worker on heroku. I am just using the worker for a get request to an external api.

Here is the error I get in my Heroku logs:

app[worker.1]: could not connect to server: No such file or directory
app[worker.1]:  connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
app[worker.1]:  Is the server running locally and accepting

Here is my config/initializers/sidekiq.rb

if Rails.env.production?

  Sidekiq.configure_client do |config|
    config.redis = { url: ENV['REDISTOGO_URL'] }
  end

  Sidekiq.configure_server do |config|
    config.redis = { url: ENV['REDISTOGO_URL'] }

    Rails.application.config.after_initialize do
      Rails.logger.info("DB Connection Pool size for Sidekiq Server before disconnect is: #{ActiveRecord::Base.connection.pool.instance_variable_get('@size')}")
      ActiveRecord::Base.connection_pool.disconnect!

      ActiveSupport.on_load(:active_record) do
        config = Rails.application.config.database_configuration[Rails.env]
        config['reaping_frequency'] = ENV['DATABASE_REAP_FREQ'] || 10 # seconds
        # config['pool'] = ENV['WORKER_DB_POOL_SIZE'] || Sidekiq.options[:concurrency]
        config['pool'] = 16
        ActiveRecord::Base.establish_connection(config)

        Rails.logger.info("DB Connection Pool size for Sidekiq Server is now: #{ActiveRecord::Base.connection.pool.instance_variable_get('@size')}")
      end
    end
  end

end

Here is my Procfile

web: bundle exec puma -C config/puma.rb
worker: bundle exec sidekiq -e production -C config/sidekiq.yml

Here is my config/sidekiq.yml

development:  
  :concurrency: 5
production:  
  :concurrency: 20
:queues:
  - default

Here is my config/initializers/redis.rb

uri = URI.parse(ENV["REDISTOGO_URL"])
REDIS = Redis.new(:url => uri)

Here is my config/puma.rb

workers Integer(ENV['WEB_CONCURRENCY'] || 2)  
threads_count = Integer(ENV['RAILS_MAX_THREADS'] || 1)
threads threads_count, threads_count

preload_app!

rackup      DefaultRackup  
port        ENV['PORT']     || 3000  
environment ENV['RACK_ENV'] || 'development'

before_fork do  
  puts "Puma master process about to fork. Closing existing Active record connections."
  ActiveRecord::Base.connection.disconnect!
end

on_worker_boot do  
  ActiveRecord::Base.establish_connection
end