def set_root_path!
       raise 'APP_ROOT is not set' unless defined?(::APP_ROOT)
       raise 'APP_ROOT is not a directory' unless File.directory?(::APP_ROOT)

       @root_path =
         # Pathname is incompatible with Windows, but Windows doesn't have
         # real symlinks so File.expand_path is safe.
         if RUBY_PLATFORM =~ /(:?mswin|mingw)/
           File.expand_path(::APP_ROOT)

         # Otherwise use Pathname#realpath which respects symlinks.
         else
           Pathname.new(::APP_ROOT).realpath.to_s
         end

       Object.const_set(:RELATIVE_APP_ROOT, ::APP_ROOT.dup) unless defined?(::RELATIVE_APP_ROOT)
       ::APP_ROOT.replace @root_path
     end
def set_root_path!
       raise 'APP_ROOT is not set' unless defined?(::APP_ROOT)
       raise 'APP_ROOT is not a directory' unless File.directory?(::APP_ROOT)

       @root_path =
         # Pathname is incompatible with Windows, but Windows doesn't have
         # real symlinks so File.expand_path is safe.
         if RUBY_PLATFORM =~ /(:?mswin|mingw)/
           File.expand_path(::APP_ROOT)

         # Otherwise use Pathname#realpath which respects symlinks.
         else
           Pathname.new(::APP_ROOT).realpath.to_s
         end

       Object.const_set(:RELATIVE_APP_ROOT, ::APP_ROOT.dup) unless defined?(::RELATIVE_APP_ROOT)
       ::APP_ROOT.replace @root_path
     end
Create a new Configuration instance, initialized with the default values.
 Set the root_path to APP_ROOT and canonicalize it.