Use env var to configure logging

src/main.rs

@@ -5,6 +5,7 @@ mod personality;
 mod queue;
 
 use commands::*;
+use tracing_subscriber::{fmt, prelude::*, EnvFilter};
 
 use std::{env, sync::Arc};
 
@@ -42,7 +43,10 @@ async fn register(ctx: CommandContext<'_>) -> Result<(), Error> {
 
 #[tokio::main]
 async fn main() -> Result<()> {
-    tracing_subscriber::fmt().init();
+    tracing_subscriber::registry()
+        .with(fmt::layer())
+        .with(EnvFilter::from_default_env())
+        .init();
 
     let token =
         env::var("DISCORD_TOKEN").expect("Expected a bot token in the environment: DISCORD_TOKEN");