partitioning example

added commented-out properties with an explanation in the
bootstrap.yml files for the source and sink sample apps

spring-xd-samples/sink/src/main/resources/bootstrap.yml

@@ -4,3 +4,7 @@ spring:
     group: testtock
     name: logger
     index: 1
+    # uncomment below to have this module consume from a specific partition
+    # in the range of 0 to N-1, where N is the upstream module's partitionCount
+    #consumerProperties:
+    #  partitionIndex: 1

spring-xd-samples/source/src/main/resources/bootstrap.yml

@@ -3,3 +3,9 @@ spring:
   bus:
     group: testtock
     name: ticker
+    # uncomment below to use the last digit of the seconds as a partition key
+    # hashcode(key) % N is then applied with N being the partitionCount value
+    # thus, even seconds should go to the 0 queue, odd seconds to the 1 queue
+    #producerProperties:
+    #  partitionKeyExpression: payload.charAt(payload.length()-1)
+    #  partitionCount: 2