Added missing C++11 feature toggle to docs

docs/configuration.md

@@ -61,6 +61,7 @@ This can be useful on certain platforms that do not provide ```std::cout``` and
 	CATCH_CONFIG_CPP11_LONG_LONG			// generates overloads for the long long type
 	CATCH_CONFIG_CPP11_OVERRIDE				// CATCH_OVERRIDE expands to override (for virtual function implementations)
 	CATCH_CONFIG_CPP11_UNIQUE_PTR			// Use std::unique_ptr instead of std::auto_ptr
+    CATCH_CONFIG_CPP11_SHUFFLE              // Use std::shuffle instead of std::random_shuffle
 
 Catch has some basic compiler detection that will attempt to select the appropriate mix of these macros. However being incomplete - and often without access to the respective compilers - this detection tends to be conservative.
 So overriding control is given to the user. If a compiler supports a feature (and Catch does not already detect it) then one or more of these may be defined to enable it (or suppress it, in some cases). If you do do this please raise an issue, specifying your compiler version (ideally with an idea of how to detect it) and stating that it has such support.