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+Extending APScheduler
+=====================
+
+This document is meant to explain how to add extra functionality to
+APScheduler, such as custom triggers or job stores.
+
+
+Writing and using custom triggers
+---------------------------------
+
+If you need to use some specialized scheduling algorithm, you can implement
+that as a custom trigger class. The only method a trigger class has to
+implement is ``get_next_fire_time``. This method receives a starting date
+(a :class:``~datetime.datetime`` object) as its sole argument, and the method
+should return the next time the trigger will fire, according to whatever
+scheduling logic you wish to implement. If no such date/time can be computed,
+it should return ``None``.
+
+To schedule a job using your custom trigger, you can either extends the 
+:class:`~apscheduler.scheduler.Scheduler` class to include your own shortcuts,
+or use the generic :meth:`~apscheduler.scheduler.Scheduler.add_job` method to
+add your jobs.
+
+
+Writing and using custom job stores
+-----------------------------------
+
+Job store classes should preferably inherit from
+:class:`apscheduler.jobstores.base.JobStore`. This class provides stubbed out
+methods which any implementation should override. These methods also contain
+useful documentation regarding the responsibilities of a job store. It is
+recommended that you look at the existing job store implementations for
+examples.
+
+To use your job store, you must add it to the scheduler as normal::
+
+  jobstore = MyJobStore()
+  scheduler.add_jobstore(jobstore)
+
+If you do not specify an explicit alias when adding the job store, it will be
+automatically determined from the class name. The class name is converted to
+lower case and the "jobstore" suffix is removed. Thus, for "MyJobStore", the
+alias would be "my". You can override the default behavior by setting the
+``default_alias`` variable in your job store.