document in readme about t configure

README.md

@@ -123,6 +123,17 @@ It is possible to access directly the sqlite database using
 
     t backend
 
+### Configuration
+
+`tiempo` keeps a config file, whose location you can learn usign `t configure`.
+It is also possible to edit the config file in-place passing arguments to
+`t configure` like this:
+
+    t c --append-notes-delimiter ';'
+
+it will print the resulting config file. Beware that it wont keep comments added
+to the file.
+
 ## Specifying times
 
 Some arguments accept a time as value, like `t in`'s `--at` or `t d --start`.