Add faq entry about autoreload [skip ci]

docs/faq.rst

@@ -2,6 +2,8 @@
  Frequently Asked Questions (FAQ)
 ==================================
 
+.. contents::
+
 How do I protect the gallery with a password?
 ---------------------------------------------
 
@@ -74,3 +76,17 @@ Sigal may (eventually?) leak information about filenames, thumbnails
 or even contents without your knowledge in the future. But it's a good
 simple way to add basic snooping protection over certain areas with
 minimal configuration.
+
+How to regenerate the gallery when something changes ?
+------------------------------------------------------
+
+It can be convenient to build continuously the gallery when adding or removing
+pictures in the albums, however Sigal does not provide currently a buitin
+"autoreload" feature. This can be achieved with external tool like `peat
+<https://github.com/sjl/peat>`_, `entr <http://entrproject.org/>`_, and probably
+many others. For instance, with peat::
+
+    peat --dynamic 'find pictures/' 'sigal build'
+
+will watch changes inside the ``pictures/`` directory and rebuild the gallery in
+this case.