move to Markdown for data and support subtasks

Cargo.toml

@@ -14,6 +14,7 @@ categories = ["command-line-utilities"]
 clap = { version = "4.5.41", features = ["derive"] }
 xdg = "3.0.0"
 termion = "2.0"
+chrono = "0.4"
 
 [dev-dependencies]
 tempfile = "3.20.0"