add section title

Author: kenjis

user_guide_src/source/general/environments.rst

@@ -27,6 +27,10 @@ The environment ``testing`` is reserved for PHPUnit testing. It has special
 conditions built into the framework at various places to assist with that.
 You can't use it for your development.
 
+*******************
+Setting Environment
+*******************
+
 .. _environment-constant:
 
 The ENVIRONMENT Constant