added missing doc for the do tag

diff --git a/doc/tags/do.rst b/doc/tags/do.rst
new file mode 100644 (file)
index 0000000..eca63d0
--- /dev/null
+++ b/doc/tags/do.rst
@@ -0,0 +1,12 @@
+``do``
+======
+
+.. versionadded:: 1.5
+    The do tag was added in Twig 1.5.
+
+The ``do`` tag works exactly like the regular variable expression (``{{ ...
+}}``) just that it doesn't print anything:
+
+.. code-block:: jinja
+
+    {% do 1 + 2 %}