Add an init script for the shell

Since I imagine there will be more of this kind of thing

init.bash

@@ -0,0 +1,6 @@
+# Source this into your shell config, e.g. ~/.zshrc
+
+# Bash scripts can't change the working directory of their callers. This is
+# right and proper, but we need to work around it in this case.
+#
+repo () { cd $($(dirname ${BASH_SOURCE[0]})/repo $@) }