fix: make build number display!

build.rs

@@ -1,3 +1,16 @@
+use std::process::Command;
+
 fn main() {
     println!("cargo:rerun-if-changed=migrations");
+
+    let git_short_hash = Command::new("git")
+        .args(["rev-parse", "--short", "HEAD"])
+        .output()
+        .ok()
+        .and_then(|o| String::from_utf8(o.stdout).ok())
+        .map(|s| s.trim().to_string())  // Trim newline
+        .unwrap_or_else(|| "UNKNOWN".to_string());
+
+    // Tell Cargo to set `GIT_SHORT_HASH` for the main compilation
+    println!("cargo:rustc-env=GIT_SHORT_HASH={}", git_short_hash);
 }