http_private: add config field db_connections_per_worker

aquatic_http_private/src/config.rs

@@ -18,6 +18,7 @@ pub struct Config {
     /// generate responses and send them back to the socket workers.
     pub request_workers: usize,
     pub worker_channel_size: usize,
+    pub db_connections_per_worker: u32,
     pub log_level: LogLevel,
     pub network: NetworkConfig,
     pub protocol: ProtocolConfig,
@@ -31,6 +32,7 @@ impl Default for Config {
             socket_workers: 1,
             request_workers: 1,
             worker_channel_size: 128,
+            db_connections_per_worker: 1,
             log_level: LogLevel::default(),
             network: NetworkConfig::default(),
             protocol: ProtocolConfig::default(),

aquatic_http_private/src/workers/socket/mod.rs

@@ -53,7 +53,7 @@ async fn run_app(
     );
 
     let pool = MySqlPoolOptions::new()
-        .max_connections(5)
+        .max_connections(config.db_connections_per_worker)
         .connect(&db_url)
         .await?;