Clarify that YAPF currently requires Python 2.7 and 3.x is planned.
diff --git a/README.rst b/README.rst
index 20a6b85..7d47212 100644
--- a/README.rst
+++ b/README.rst
@@ -32,11 +32,13 @@
 Installation
 ============
 
-From source directory::
+YAPF currently requires Python 2.7; support for Python 3.x is planned in the
+near future.
+
+To install YAPF from the source directory::
 
     $ sudo python ./setup.py install
 
-
 Usage
 =====