mention what to do on debian wheezy

README.md

@@ -31,6 +31,15 @@ update the package sources, and install the `liber` package:
     $ sudo apt-get update
     $ sudo apt-get install liber
 
+*Note*: on Debian Wheezy, you will need to install the `libleveldb1`
+package from the backports repository (see the
+[Debian backports website](http://backports.debian.org/) for
+instructions on how to set that up) before running the commands
+mentioned above:
+
+    $ apt-get install -t wheezy-backports libleveldb1
+
+
 ### Build from source
 
 The source has a few dependencies: