add config class and schedule

lib/periodicity/cli.rb

@@ -1,4 +1,5 @@
 module Periodicity
   class Cli
+    
   end
 end

lib/periodicity/config.rb

@@ -0,0 +1,11 @@
+module Periodicity
+  class Config
+    include Singleton
+
+    attr_accessor :schedule
+
+    def initialize
+      self.schedule = []
+    end
+  end
+end

lib/periodicity/extensions/active_job.rb

@@ -2,7 +2,7 @@ module Periodicity
   module Extensions
     module ActiveJob
       def perform_every(period, *args)
-        @period = Period.new(period, *args)
+        Config.instance.schedule += [self, Period.new(period, *args)]
       end
     end
   end