adds command to rollback a release of an app

README.md

@@ -177,6 +177,28 @@ Version: 3
 Status: succeeded
 ```
 
+**~rollback_app**
+
+If you would like to rollback your app to the code associated with a previous release of your app, you can do so with the ~rollback_app command.
+
+```
+you: ~rollback_app testing-nell-bot version-to-rollback-to
+```
+
+```
+you: ~rollback_app testing-nell-bot v5
+
+crates-io-bot: @you App testing-nell-bot was successfully rolled back to the code at v5
+```
+
+You can either specify the version with a "v" before the version number or with just the number. This command will also work.
+
+```
+you: ~rollback_app testing-nell-bot 5
+
+crates-io-bot: @you App testing-nell-bot was successfully rolled back to the code at 5
+```
+
 **~scale_app**
 
 You can scale formations of dynos within your application through the ~scale_app command.

src/commands/heroku.rs

@@ -169,6 +169,38 @@ pub fn get_app_releases(ctx: &mut Context, msg: &Message, mut args: Args) -> Com
     Ok(())
 }
 
+#[command]
+#[num_args(2)]
+pub fn rollback_app(ctx: &mut Context, msg: &Message, mut args: Args) -> CommandResult {
+    let app_name = args
+        .single::<String>()
+        .expect("You must include an app name");
+
+    let version_to_rollback_to = args
+        .single::<String>()
+        .expect("You must include the version to roll back to");
+
+    let response = heroku_client(ctx).request(&releases::ReleaseRollback {
+        app_id: app_name.clone(),
+        params: releases::ReleaseRollbackParams {
+            release: version_to_rollback_to.clone(),
+        },
+    });
+
+    msg.reply(
+        ctx,
+        match response {
+            Ok(_response) => format!(
+                "App {} was successfully rolled back to the code at {}",
+                app_name, version_to_rollback_to
+            ),
+            Err(e) => format!("An error occured when trying to roll back your app:\n{}", e),
+        },
+    )?;
+
+    Ok(())
+}
+
 #[command]
 pub fn get_apps(ctx: &mut Context, msg: &Message, _args: Args) -> CommandResult {
     let response = heroku_client(ctx).request(&apps::AppList {});

src/lib.rs

@@ -29,7 +29,8 @@ use crate::authorizations::users::*;
     restart_app,
     scale_app,
     update_app_config,
-    get_app_releases
+    get_app_releases,
+    rollback_app
 )]
 struct General;