Added make doxygen-doc
diff --git a/INSTALL b/INSTALL
index e9f33e0..d719c99 100644
--- a/INSTALL
+++ b/INSTALL
@@ -16,6 +16,9 @@
 
 (There is currently no "install" step.)
 
+To make documentation, enter:
+make doxygen-doc
+
 Files
 -----
 
@@ -30,6 +33,9 @@
 bin/test-encode-decode-interest: Encode and decode an interest, testing interest selectors and the name URI.
 bin/test-encode-decode-data: Encode and decode a data packet, including signing the data packet.
 
+Running make doxygen-doc puts code documentation in:
+doc/html
+
 Supported platforms
 -------------------