Add repo add and repo show commands

gdn/src/repo/v0.rs

@@ -0,0 +1,20 @@
+use std::collections::HashMap;
+
+use super::v1;
+
+pub const VERSION: u32 = 0;
+
+pub struct Repo;
+
+impl Repo {
+    pub fn load() -> Self {
+        Self
+    }
+
+    pub fn migrate(self) -> super::Repo {
+        v1::Repo {
+            notes: HashMap::new(),
+        }
+        .migrate()
+    }
+}