Add docs/intro to simple_linear example

Change-Id: I6911337bf492d5cfc7e48a006dbf076826a18a62

taskflow/examples/simple_linear.py

@@ -31,29 +31,37 @@ import taskflow.engines
 from taskflow.patterns import linear_flow as lf
 from taskflow import task
 
+# INTRO: In this example we create two tasks, each of which ~calls~ a given
+# ~phone~ number (provided as a function input) in a linear fashion (one after
+# the other). For a workflow which is serial this shows a extremly simple way
+# of structuring your tasks (the code that does the work) into a linear
+# sequence (the flow) and then passing the work off to an engine, with some
+# initial data to be ran in a reliable manner.
+#
+# This example shows a basic usage of the taskflow structures without involving
+# the complexity of persistence. Using the structures that taskflow provides
+# via tasks and flows makes it possible for you to easily at a later time
+# hook in a persistence layer (and then gain the functionality that offers)
+# when you decide the complexity of adding that layer in is 'worth it' for your
+# applications usage pattern (which some applications may not need).
+
 
 class CallJim(task.Task):
-
-    def __init__(self):
-        super(CallJim, self).__init__()
-
     def execute(self, jim_number, *args, **kwargs):
         print("Calling jim %s." % jim_number)
 
 
 class CallJoe(task.Task):
-
-    def __init__(self):
-        super(CallJoe, self).__init__()
-
     def execute(self, joe_number, *args, **kwargs):
         print("Calling joe %s." % joe_number)
 
 
+# Create your flow and associated tasks (the work to be done).
 flow = lf.Flow('simple-linear').add(
     CallJim(),
     CallJoe()
 )
 
+# Now run that flow using the provided initial data (store below)
 taskflow.engines.run(flow, store=dict(joe_number=444,
                                       jim_number=555))