add feedback gen command

README.md

@@ -3,6 +3,12 @@
 horizon-plutus is an overlay for horizon-platform containing cardano and plutus
 libraries
 
+## development with feedback
+
+You can get live feedback using the
+[feedback](https://hackage.haskell.org/package/feedback) tool and
+running the following commands in three separate terminals
+
 ```
 feedback build
 ```
@@ -10,3 +16,7 @@ feedback build
 ```
 feedback check
 ```
+
+```
+feedback gen
+```

feedback.yaml

 loops:
   build: cat .build-all.dhall | dhall text | bash
   check: nix flake check -L
+  gen:
+    command: nix run .#horizon-gen-nix overlay
+    filter:
+      find: horizon.dhall