deprecation warning about log level in master

DEPRECATION WARNING: You did not specify a `log_level` in `production.rb`. Currently, the default value for `log_level` is `:info` for the production environment and `:debug` in all other environments. In Rails 5 the default value will be unified to `:debug` across all environments. To preserve the current setting, add the following line to your `production.rb`:

   config.log_level = :info

. (called from block in tsort_each at /usr/lib64/ruby/2.2.0/tsort.rb:226)