Persist cargo's cache
- Compiling rust programs will be far slower if cargo doesn't cache
diff --git a/modules/rust.nix b/modules/rust.nix
new file mode 100644
index 0000000..71339fa
--- /dev/null
+++ b/modules/rust.nix
@@ -0,0 +1,5 @@
+{username, ...}: {
+ # Rust should be installed via direnv *not* here, however we still need to persist the cache
+ # as we don't want installing crates to be slower than it has to be
+ config.environment.persistence."/nix/persist".users.${username}.directories = [".cargo"];
+}