main.rs: Accept a ref as a command line argument

If a ref is given on the command line, use that as the diff base.
Otherwise default to master.

1 files changed, 2 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 834bb4c..69bbb52 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,5 +4,7 @@ version = "0.0.1"
 edition = "2018"
 
 [dependencies]
+exitcode = "1.1.2"
+getopts = "0.2.21"
 git2 = "0.13.11"
 thiserror = "1.0.20"