Debug log docs (SeaQL/sea-orm#114)

SeaORM/docs/01-index.md

@@ -18,6 +18,8 @@
 
 	1.3 [Connection Pool](/docs/install-and-config/connection)
 
+	1.4 [Debug Log](/docs/install-and-config/debug-log)
+
 2. Generating Entities
 
 	2.1 [Using `sea-orm-cli`](/docs/generate-entity/sea-orm-cli)

SeaORM/docs/02-install-and-config/04-debug-log.md

@@ -0,0 +1,20 @@
+# Debug Log
+
+The SeaORM and the underlying database driver [`SQLx`](https://crates.io/crates/sqlx) both log debug messages via [`log`](https://crates.io/crates/log) crate.
+
+You need to choose one of the [logging implementations](https://docs.rs/log/0.4.14/log/#available-logging-implementations) to capture and view the debug log. We recommand using [`env_logger`](https://crates.io/crates/env_logger), you can see the snippet below and a complete example [here](https://github.com/SeaQL/sea-orm/blob/master/examples/tokio/src/main.rs).
+
+```rust
+pub async fn main() {
+    env_logger::builder()
+        .filter_level(log::LevelFilter::Debug)
+        .is_test(true)
+        .init();
+
+    let db = Database::connect("mysql://sea:sea@localhost/bakery")
+        .await
+        .unwrap();
+
+    cake::Entity::find().one(&db).await.unwrap();
+}
+```