Use more async API from tokio

Fixes issue #4

src/main.rs

@@ -1,8 +1,6 @@
 use structopt::StructOpt;
 use std::{
     path::PathBuf,
-    fs::File,
-    io::prelude::*,
     boxed::Box,
     error::Error,
 };
@@ -20,6 +18,8 @@ use sqlx::{
 };
 use tokio::{
     sync::RwLock,
+    fs::File,
+    io::AsyncReadExt,
 };
 
 const DEFAULT_DATABASE_PATH: &'static str = "/var/lib/noise-server/noise-server.sqlite";
@@ -67,7 +67,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
         return Ok(());
     }
 
-    let mut config = get_config(&options)?;
+    let mut config = get_config(&options).await?;
 
     if clap_matches.is_present("database-path") {
         config.database_path = options.database_path;
@@ -106,13 +106,13 @@ async fn load_sqlite_template(sqlite_handle: &mut SqliteConnection) -> sqlx::Res
     )).execute(sqlite_handle).await
 }
 
-fn get_config(options: &Options) -> std::io::Result<Config> {
+async fn get_config(options: &Options) -> std::io::Result<Config> {
     if options.no_config {
         Ok(Config::default())
     } else {
-        let mut config_file = File::open(&options.config)?;
+        let mut config_file = File::open(&options.config).await?;
         let mut config_string = String::new();
-        config_file.read_to_string(&mut config_string)?;
+        config_file.read_to_string(&mut config_string).await?;
 
         toml::from_str(&config_string)
             .map_err(|err| std::io::Error::new(