Merge #257: docs: crate docs for lib.rs

78f295b docs: [#253] crate docs for app.rs (Jose Celano)
a58554a docs: [#253] crate docs for lib.rs (Jose Celano)

Pull request description:

  Entrypoint for the crate documentation, the `lib.rs` file.

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Tree-SHA512: ec13ffc6408f3cf06da59cf639807e11b8e5baecbcad016ec8662753ff53cc9e971bff1e9ae3979ae729def9f3ab8a63d884584dba4a56d58fb0c8510c3daf1d

Author: josecelano

cSpell.json

@@ -7,6 +7,7 @@
         "Azureus",
         "bencode",
         "bencoded",
+        "beps",
         "binascii",
         "Bitflu",
         "bools",

docs/media/torrust-tracker-components.png

@@ -1,3 +1,22 @@
+//! Torrust Tracker application.
+//!
+//! The tracker application has a global configuration for multiple jobs.
+//! It's basically a container for other services.
+//! It also check constraint and dependencies between services. For example:
+//! It's not safe to run a UDP tracker on top of a core public tracker, as UDP trackers
+//! do not allow private access to the tracker data.
+//!
+//! The application is responsible for:
+//!
+//! - Loading data from the database when it's needed.
+//! - Starting some jobs depending on the configuration.
+//!
+//! The started jobs may be:
+//!
+//! - Torrent cleaner: it removes inactive peers and (optionally) peerless torrents.
+//! - UDP trackers: the user can enable multiple UDP tracker on several ports.
+//! - HTTP trackers: the user can enable multiple HTTP tracker on several ports.
+//! - Tracker REST API: the tracker API can be enabled/disabled.
 use std::sync::Arc;
 
 use log::warn;