def config_file(filename)
      if filename =~ /^\//
        @config_file = filename
      else
        @config_file = File.join(File.expand_path(ENV['HOME']),filename)
      end
      commands[:initconfig] = InitConfig.new(@config_file,commands,flags,switches)
      @commands_declaration_order << commands[:initconfig]
      @config_file
    end
def config_file(filename)
      if filename =~ /^\//
        @config_file = filename
      else
        @config_file = File.join(File.expand_path(ENV['HOME']),filename)
      end
      commands[:initconfig] = InitConfig.new(@config_file,commands,flags,switches)
      @commands_declaration_order << commands[:initconfig]
      @config_file
    end
Sets that this app uses a config file as well as the name of the config file.

 +filename+:: A String representing the path to the file to use for the config file.  If it's an absolute
              path, this is treated as the path to the file.  If it's *not*, it's treated as relative to the user's home
              directory as produced by <code>File.expand_path('~')</code>.