impl Hash for ValueBase - so we can store them in a hashmap! (#188)

* impl Hash for ValueBase - so we can store them in a hashmap!

taiga_halo2/src/note.rs

@@ -23,7 +23,10 @@ use pasta_curves::{
     pallas,
 };
 use rand::{Rng, RngCore};
-use std::io;
+use std::{
+    hash::{Hash, Hasher},
+    io,
+};
 
 /// A commitment to a note.
 #[derive(Copy, Debug, Clone)]
@@ -406,6 +409,13 @@ impl ValueBase {
     }
 }
 
+impl Hash for ValueBase {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.app_vk.to_repr().as_ref().hash(state);
+        self.app_data_static.to_repr().as_ref().hash(state);
+    }
+}
+
 impl RandomSeed {
     pub fn random<R: RngCore>(mut rng: R) -> Self {
         let mut rseed = [0; 32];