use overmind to start everything

Procfile

@@ -0,0 +1,5 @@
+db: trap 'docker stop souplesse-postgres' EXIT > /dev/null;  docker run --rm -p 5432:5432 --name souplesse-postgres -e POSTGRES_USER=souplesse  -e POSTGRES_PASSWORD=secret postgres
+psql: nix-shell -p postgresql --run "psql -h localhost -U souplesse   -p 5432"
+build: git ls-files | entr make
+elm-repl: elm repl
+serve: cabal run

default.nix

@@ -11,9 +11,11 @@ let
         ]);
   };
 in haskellEnv.overrideAttrs(o: {
+  OVERMIND_AUTO_RESTART = "all";
   buildInputs = o.buildInputs ++
                 (with pkgs.elmPackages; [
                   pkgs.entr
+                  pkgs.overmind
                   elm
                   elm-format
                   elm-optimize-level-2