setup.md: Add some notes about tuning

Solves: Jira GER-2365
Change-Id: I17393eb0439a689bb7eaef7ee0c3dcbf846a19f1
diff --git a/src/main/resources/Documentation/setup.md b/src/main/resources/Documentation/setup.md
index 4cbe2cc..3330ed9 100644
--- a/src/main/resources/Documentation/setup.md
+++ b/src/main/resources/Documentation/setup.md
@@ -19,3 +19,27 @@
 truth and the Eiffel Repostory APIs aren't necessary. The side-effect is that
 inconsistencies may follow if events are sent by others than the events-eiffel
 plugin.
+
+## Tuning
+
+### RabbitMQ
+
+#### Confirms
+
+By default the RabbitMQ publisher waits for confirms for 5 seconds. If you have
+high latency on your network you might want to increase this value in the config
+`RabbitMq.waitForConfirms`.
+If performance is more important to you than the risk of losing events you can
+disable confirms by setting it to `0`.
+
+#### Batch
+
+The overhead of sending one message when `waitForConfirm` is enabled is quite
+large so you might want to increase the batch size from the default `1` by
+setting `RabbitMq.maxBatchSize` to `10` and increase more if necessary.
+This means that the publisher will publish and confirm messages in batches
+of 10.
+
+The batch size is maximum 10 in this case, if the queue only contains 2 events
+it will not wait until 8 more events are added to the queue but instead send
+those 2 events in one batch.