add doc-comment to note.rs; add .env.sample; ignore .env

.env.sample

@@ -0,0 +1,7 @@
+# if `GITHUB_API_TOKEN` is not set here, the token can also be stored in `~/.gitconfig`
+GITHUB_API_TOKEN=MUST_BE_CONFIGURED
+DATABASE_URL=MUST_BE_CONFIGURED
+GITHUB_WEBHOOK_SECRET=MUST_BE_CONFIGURED
+# for logging, refer to this document: https://rust-lang-nursery.github.io/rust-cookbook/development_tools/debugging/config_log.html
+# `RUSTC_LOG` is not required to run the application, but it makes local development easier
+# RUST_LOG=MUST_BE_CONFIGURED

.gitignore

@@ -1,2 +1,3 @@
 /target
-**/*.rs.bk
+**/*.rs.bk
+.env

src/handlers/note.rs

@@ -1,3 +1,40 @@
+//! Allow users to add summary comments in Issues & Pull Requests.
+//!
+//! Users can make a new summary entry by commenting the following:
+//!
+//! ```md
+//! @rustbot note summary-title
+//!
+//! ...details details details...
+//! ```
+//!
+//! If this is the first summary entry, rustbot will amend the original post (the top-level comment) to add a "Notes" section:
+//!
+//! ```md
+//! <!-- rustbot summary start -->
+//!
+//! ### Notes
+//!
+//! - ["summary-title" by @username](link-to-comment)
+//!
+//! <!-- rustbot summary end -->
+//! ```
+//!
+//! If this is *not* the first summary entry, rustbot will simply append the new entry to the existing notes section:
+//!
+//! ```md
+//! <!-- rustbot summary start -->
+//!
+//! ### Notes
+//!
+//! - ["first-note" by @username](link-to-comment)
+//! - ["second-note" by @username](link-to-comment)
+//! - ["summary-title" by @username](link-to-comment)
+//!
+//! <!-- rustbot summary end -->
+//! ```
+//!
+
 use crate::{
     config::NoteConfig,
     github::{self, Event, Selection},
@@ -22,15 +59,12 @@ pub(super) async fn handle_command(
 ) -> anyhow::Result<()> {
     log::debug!("Handling Note Command");
 
-    // TODO: edit the original post to include:
-    //
-    // ```md
-    // <!-- start rustbot summary-->
-    // - [title](LINK_TO_SUMMARY_COMMENT)
-    // <!-- end rustbot summary-->
-    // ```
+    // TODO: edit the original post
 
     let issue = event.issue().unwrap();
+    
+    log::debug!("Issue: {:?}", issue);
+
     if issue.is_pr() {
         let NoteCommand::Summary { title, summary } = &cmd;
         log::debug!("Note: {}, {}", title, summary);