feat(backend, lb) add missing components

backend/server/build.rs

@@ -0,0 +1,15 @@
+use chrono::Utc;
+use git2::Repository;
+
+fn main() {
+    let repo = Repository::open("../..").expect("failed to open repository");
+    let commit = repo
+        .head()
+        .expect("failed to get HEAD")
+        .peel_to_commit()
+        .expect("failed to get HEAD commit");
+    let hash = commit.id().to_string();
+    let utc_date = Utc::now().date_naive().format("%Y%m%d").to_string();
+    let build_id = format!("{}@{}", utc_date, &hash[..8]);
+    println!("cargo:rustc-env=BUILD_ID={}", build_id);
+}