README.md in cloudformation-ruby-dsl-0.4.12 vs README.md in cloudformation-ruby-dsl-0.4.13

@@ -71,5 +71,9 @@
 - `tag(tag)`: add tags to the stack, which are inherited by all resources in that stack; can only be used at launch
 - `file(name)`: return the named file as a string, for further use
 - `load_from_file(filename)`: load the named file by a given type; currently handles YAML, JSON, and Ruby
 - `interpolate(string)`: embed CFN references into a string (`{{ref('Service')}}`) for later interpretation by the CFN engine
 - `Table.load(filename)`: load a table from the listed file, which can then be turned into mappings (via `get_map`)
+
+### Default Region
+
+The tool defaults to region 'us-east-1'. To change this set either 'EC2_REGION' or 'AWS_DEFAULT_REGION' environment variables.