[doc] added documentation for the ignore_invalid_variables option

diff --git a/doc/03-Twig-for-Developers.markdown b/doc/03-Twig-for-Developers.markdown
index 463a698..ee55dc1 100644 (file)
--- a/doc/03-Twig-for-Developers.markdown
+++ b/doc/03-Twig-for-Developers.markdown
@@ -93,6 +93,13 @@ The following options are available:
    the `auto_reload` option, it will be determined automatically based on the
    `debug` value.
 
+ * `ignore_invalid_variables` (new in Twig 0.9.7): If set to `true`, Twig will
+   silently ignore invalid variables (variables and or attributes/methods that
+   do not exist) and replace them with a `null` value. When set to `false`,
+   Twig throws an exception instead. If you don't provide a value for the
+   `ignore_invalid_variables` option, it will be determined automatically
+   based on the `debug` value (`false` when in debug mode, `true` otherwise).
+
 >**CAUTION**
 >Before Twig 0.9.3, the `cache` and `auto_reload` options did not exist. They
 >was passed as a second and third arguments of the filesystem loader