Allow developers to use nix-shell to get started

shell.nix

@@ -0,0 +1,39 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+pkgs.mkShell {
+  buildInputs = [ pkgs.postgresql pkgs.redis ];
+
+  shellHook = ''
+    echo "Setting up PostgreSQL environment..."
+    export PGDATA=$(mktemp -d)
+    PG_SOCKET_DIR=$(mktemp -d)
+    echo "Initializing database..."
+    initdb $PGDATA
+
+    echo "Starting PostgreSQL with custom socket directory..."
+    pg_ctl -D $PGDATA -o "-k $PG_SOCKET_DIR" -l logfile start
+
+    # Wait a bit for the server to start
+    sleep 1
+
+    # Create the 'aleph' role and a database
+    createuser -h $PG_SOCKET_DIR aleph
+    createdb -h $PG_SOCKET_DIR aleph -O aleph
+
+    # Create a temporary directory for Redis
+    export REDIS_DATA_DIR=$(mktemp -d)
+    redis-server --daemonize yes --dir $REDIS_DATA_DIR --bind 127.0.0.1 --port 6379
+    echo "Redis server started. Data directory is $REDIS_DATA_DIR"
+
+    # Trap the EXIT signal to ensure PostgreSQL is stopped when exiting the shell
+    trap 'echo "Stopping PostgreSQL..."; pg_ctl -D "$PGDATA" stop; echo "Stopping Redis..."; redis-cli -p 6379 shutdown' EXIT
+
+    echo
+    echo "PostgreSQL started. Data directory is $PGDATA, Socket directory is $PG_SOCKET_DIR"
+    echo "Redis started. Data directory is $REDIS_DATA_DIR"
+    echo "Use 'psql -h $PG_SOCKET_DIR' to connect to the database."
+    echo "Use 'redis-cli -p 6379' to connect to the Redis server."
+    echo "To stop PostgreSQL: 'pg_ctl -D $PGDATA stop'"
+    echo "To manually stop Redis: 'redis-cli -p 6379 shutdown'"
+  '';
+}