Clarifying the data to be passed into the pillar command

Author: ev0rtex

README.rst

@@ -172,9 +172,9 @@ Miscellaneous
 Pillar Data
 -----------
 
-You can export pillar data for use during provisioning by using the ``pillar``
-command. Each call will merge the data so you can safely call it multiple
-times.  Here is an example::
+You can export pillar data for use during provisioning by using the ``pillar`` 
+command. Each call will merge the data so you can safely call it multiple 
+times. The data passed in should only be hashes and lists. Here is an example::
 
       config.vm.provision :salt do |salt|