use .contract file extension for stockpile dirs

examples/dao/data/.gitignore

@@ -1,4 +1,4 @@
-WonderlandDAO
-*.schema
+*.contract
+*.issuer
 *.deeds
 *.articles

examples/dao/main.rs

@@ -115,7 +115,7 @@ fn main() {
     // Creating DAO with three participants
     let issuer = Schema::new(codex, api, [libs::success()], types.type_system());
     issuer
-        .save("examples/dao/data/SimpleDAO.schema")
+        .save("examples/dao/data/SimpleDAO.issuer")
         .expect("unable to save issuer to a file");
 
     let seed = &[0xCA; 30][..];

src/stock.rs

@@ -386,6 +386,7 @@ pub mod fs {
         pub fn new(name: &str, path: impl AsRef<Path>) -> Self {
             let mut path = path.as_ref().to_path_buf();
             path.push(name);
+            path.set_extension("contract");
             fs::create_dir_all(&path).expect("Unable to create directory to store Stock");
 
             let stash = FileAora::new(&path, "stash");