More realistic debug message

src/app.md

@@ -119,14 +119,34 @@ The `log` crate provides logging utilities. The `env_logger` crate configures
 logging via an environment variable.
 
 ```rust
-#[macro_use] extern crate log;
+#[macro_use]
+extern crate log;
 extern crate env_logger;
+#
+# #[macro_use]
+# extern crate error_chain;
+#
+# error_chain! {
+#    foreign_links {
+#        SetLogger(log::SetLoggerError);
+#    }
+# }
 
-fn main() {
-    env_logger::init().unwrap();
+fn execute_query(query: &str) {
+    debug!("Executing query: {}", query);
 
-    debug!("this is a debug {}", "message");
+    // then do the thing
 }
+
+fn run() -> Result<()> {
+    env_logger::init()?;
+
+    execute_query("DROP TABLE students");
+
+    Ok(())
+}
+#
+# quick_main!(run);
 ```
 
 If you run this code, you'll notice that no output is printed. By default, the
@@ -142,7 +162,7 @@ After running this, you'll likely see a pile of logs from cargo, as well as the
 following line at the very end of the output:
 
 ```
-DEBUG:main: this is a debug message
+DEBUG:main: Executing query: DROP TABLE students
 ```
 
 [ex-log-error]: #ex-log-error