chore: add Makefile and git hooks

.hooks/pre-commit

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+set -eu
+
+if ! cargo fmt -- --check
+then
+    echo "There are some code style issues."
+    echo "Run cargo fmt first."
+    exit 1
+fi
+
+if ! cargo clippy --all-targets -- -D warnings
+then
+    echo "There are some clippy issues."
+    exit 1
+fi
+
+if ! cargo test
+then
+    echo "There are some test issues."
+    exit 1
+fi
+
+exit 0

Makefile

@@ -0,0 +1,20 @@
+fmt:
+	@cargo fmt
+
+build:
+	@cargo build
+
+clean: 
+	@cargo clean
+
+test:
+	@cargo test
+
+lint: fmt
+	@cargo clippy --all-targets -- -D warnings
+
+git-hooks:
+	@echo "Installing git hooks..."
+	@cp -r .hooks/* .git/hooks/
+	@chmod +x .git/hooks/*
+	@echo "Done."

src/formatter.rs

@@ -210,8 +210,7 @@ mod tests {
 
     use super::*;
     use chrono::Utc;
-    use tracing::{debug, error, info, info_span, trace, warn};
-    use tracing_core::Level;
+    use tracing::{info, info_span};
     use tracing_subscriber::fmt::{MakeWriter, SubscriberBuilder};
 
     #[derive(Clone, Debug)]

src/lib.rs

@@ -21,6 +21,8 @@
 //! ```
 //!
 //! ```rust
+//! use tracing_subscriber::prelude::*;
+//!
 //! tracing_subscriber::registry()
 //!     .with(tracing_ndjson::builder().layer())
 //!     .init();