Update README

README.md

@@ -1 +1,22 @@
 # git-repo-updater
+
+`git-repo-updater` is an CLI program that finds and updates Git repositories in specified directories.
+
+## Configuration
+
+`git-repo-updater` is configurable using a configuration file at `~/.config/git-repo-updater/config.yaml`.
+
+For example:
+
+```yaml
+# The number of levels to search.
+depth: 3
+
+# A list of directories to search in.
+directories:
+  - ~/Code/code.oliverdavies.uk
+
+# A list of repositories to ignore and not update.
+ignored:
+  - ~/Code/github.com/nixos/nixpkgs
+```