feat: add completions subcommand

src/cli/ahab.rs

@@ -1,5 +1,6 @@
 use super::{Django, DockerCompose, Link, Postgres};
 use clap::{Parser, Subcommand};
+use clap_complete::Shell;
 
 /// A program for interacting with various dockerized applications.
 #[derive(Parser, Debug)]
@@ -34,4 +35,10 @@ pub enum Commands {
         #[command(subcommand)]
         command: Link,
     },
+
+    /// Print a shell completion script on stdout
+    Completions {
+        /// Shell to generate the script for
+        shell: Shell,
+    },
 }