Add helper script to launch the dev shell

hall.scm

@@ -16,7 +16,10 @@
               ((scheme-file "docs") (scheme-file "reflection")))
             (scheme-file "guile-docs")))
          (tests ())
-         (programs ())
+         (programs
+           ((directory
+              "scripts"
+              ((text-file "launch-dev-shell")))))
          (documentation
            ((directory "doc" ((texi-file "guile-docs")))
             (text-file "COPYING")

manifest.scm

@@ -2,4 +2,4 @@
 ;; You can store it in a file that you may then pass to any 'guix' command
 ;; that accepts a '--manifest' (or '-m') option.
 
-(specifications->manifest (list "guix" "git"))
+(specifications->manifest (list "guile-hall" "guix" "git"))

scripts/launch-dev-shell

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+guix shell -Df guix.scm -m manifest.scm "$@"