switch to clap's derive macros

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

src/cli.rs

@@ -0,0 +1,31 @@
+use clap::{crate_version, Clap};
+
+#[derive(Clap)]
+#[clap(version = crate_version!(), author = "Harsh Shandilya <me@msfjarvis.dev>")]
+pub(crate) struct Opts {
+    #[clap(subcommand)]
+    pub(crate) subcommand: SubCommand,
+}
+
+#[derive(Clap)]
+pub(crate) enum SubCommand {
+    Freeze(Freeze),
+    Thaw(Thaw),
+}
+
+/// recursively find git repos and record their states into a lockfile
+#[derive(Clap)]
+pub(crate) struct Freeze {
+    /// directory to search and freeze repos from.
+    pub(crate) directory: String,
+}
+
+/// takes the given
+#[derive(Clap)]
+pub(crate) struct Thaw {
+    /// directory to put cloned repos into.
+    pub(crate) directory: String,
+    /// the lockfile to restore repositories from.
+    #[clap(default_value = "gitice.lock")]
+    pub(crate) lockfile: String,
+}