diff --git a/.gitignore b/.gitignore
index f02af27..2b05435 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 *.pyc
+*.egg
 build/
 dist/
 *.egg-info/
diff --git a/CHANGES.rst b/CHANGES.rst
index da98924..df3a6d1 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -2,8 +2,8 @@
  Dirtools Changelog
 ====================
 
-0.1.1 (not released yet)
-========================
+0.1.1 (2013-12-12)
+==================
 
 - New ``compress_to`` methods for easy gzip compression with tarfile.
 - Added patterns support to ``Dir.files`` and ``Dir.subdirs`` methods.
@@ -11,13 +11,15 @@
  allowing custom sort options and abspath args that allow to choose between relative/absolute path.
 - Added Dir.size method to recursively compute directory size.
 - New ``DirState`` and ``compute_diff`` method.
-- Now skipping symlinks
+- Now skipping symlinks.
+
 
 0.1.0 (2013-07-01)
 ==================
 
 - v0.1.0 on pypi.
 
+
 0.0.0 (2013-06-17)
 ==================
 
diff --git a/README.rst b/README.rst
index eeb622e..126d50e 100644
--- a/README.rst
+++ b/README.rst
@@ -7,6 +7,8 @@ Dirtools is a little Python package aimed to provide the following features:
 * Exclude/ignore files in a directory, using .gitignore like syntax (unix filename pattern matching).
 * Generate a hash for a directory tree in order to check if a directory has been modified.
 * Search recursively for all subidirs containing a given filename (all projects directory inside a dir).
+* Track changes in a directory over time (without duplicating it or without having direct access to it).
+
 
 .. image:: https://pypip.in/v/dirtools/badge.png
         :target: https://crate.io/packages/dirtools
@@ -101,6 +103,28 @@ Or if you want to do it manually:
         tar.add(filename, arcname=arcname, exclude=d.is_excluded)
 
 
+Track changes in directories
+----------------------------
+
+Dirtools provides an helper ``DirIndex`` to help tracking changes in a directory over time, without duplicating it or without having direct access to it.
+
+.. code-block:: python
+
+    from dirtools import Dir, DirIndex
+
+    d = Dir(path)
+    dir_index = DirIndex(d)
+
+    index_file = dir_index.to_json()
+
+    # Later... after some changes
+
+    dir_index = DirIndex.from_json(index_file)
+    dir_index2 = DirIndex(d)
+
+    changes = dir_index2 - dir_index
+
+
 Helpers
 -------
 
diff --git a/dirtools.py b/dirtools.py
index 8d0211a..b65879a 100644
--- a/dirtools.py
+++ b/dirtools.py
@@ -310,6 +310,7 @@ def compress_to(self, archive_path=None):
 
 
 class DirState(object):
+    """ Hold a directory state / snapshot meta-data for later comparison. """
     def __init__(self, _dir=None, state=None, index_cmp=os.path.getmtime):
         self._dir = _dir
         self.index_cmp = index_cmp
@@ -336,7 +337,7 @@ def index(self):
     def __sub__(self, other):
         """ Compute diff with operator overloading.
 
-        >>> path =DirState(Dir('/path'))
+        >>> path = DirState(Dir('/path'))
         >>> path_copy = DirState(Dir('/path_copy'))
         >>> diff =  path_copy - path
         >>> # Equals to