Add command line docs.

TODO.md

@@ -5,7 +5,7 @@ TODO
 * [X] Figure out project config details
 * [X] Better console output
 * [X] Allow specifying the bucket/local dir from command line
-* [ ] Document usage
+* [X] Document usage
 
 Bugs
 ----

src/leiningen/s3_sync.clj

@@ -9,7 +9,23 @@
 
 (def padding "                                           ")
 
-(defn s3-sync [project & keys]
+(defn s3-sync
+  "Synchronise a directory with a bucket on Amazon's S3.
+  
+   The sync is operates recursively within the local
+   file directory. Files are compared by MD5 hash with
+   their remote equivalent and pushed if it does not
+   exist or has been changed locally. The synchonisation
+   is controlled by config specified on the command line
+   or in the project.clj:
+  
+   :s3-sync {:access-key \"XXX\"
+             :secret-key \"XXX\"
+             :bucket \"my-bucket\"
+             :local-dir \"out/public\"}
+  
+  The bucket name given must exist and be accessible."
+  [project & keys]
   (let [[valid config errors] (cl/resolve-config project keys)]
     (if (not valid)
       (lein/abort (first errors))