feat(ariadne): add graph module

src/ariadne/BUILD

@@ -3,7 +3,11 @@ load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_library")
 rust_library(
     name = "ariadne_lib",
     crate_name = "ariadne",
-    srcs = ["lib.rs"],
+    crate_root = "lib.rs",
+    srcs = [
+        "graph.rs",
+        "lib.rs",
+    ],
 )
 
 rust_binary(