Add a make install instruction to the README.
diff --git a/README b/README
index ea68fe3..655c6b4 100644
--- a/README
+++ b/README
@@ -59,6 +59,10 @@
 % ./configure
 % make
 
+3) Install the codec libraries (optional)
+
+% sudo make install
+
 Once you have compiled the codec, there will be a opus_demo executable
 in the top directory.