Dev environment setup

programs/direnv/shells/dodona.nix

@@ -0,0 +1,33 @@
+let
+  pkgs = import <nixpkgs> {};
+in
+  pkgs.mkShell {
+    buildInputs = with pkgs; [
+      ruby
+      yarn
+      nodejs-12_x
+      libmysqlclient
+      zlib
+      (pkgs.writeScriptBin "start-db" ''
+        #!${pkgs.zsh}/bin/zsh
+
+        _sighandler() {
+          docker stop dodona-db
+        }
+
+        trap _sighandler SIGINT
+        trap _sighandler SIGTERM
+        trap _sighandler SIGHUP
+
+        docker run --name dodona-db -p 3306:3306 --rm -v $(git rev-parse --show-toplevel)/tmp/db:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=dodona mariadb:latest &
+
+        child=$!
+        wait $child
+        # We wait two times, because the first wait exits when the process receives a signal. The process might have finished though, so we ignore errors.
+        wait $child 2>/dev/null
+      '')
+    ];
+    shellHook = ''
+      export DATABASE_URL="mysql2://root:dodona@127.0.0.1:3306/dodona"
+    '';
+  }