gnu: Add git-cal.

* gnu/packages/version-control.scm (git-cal): New variable.

gnu/packages/version-control.scm

@@ -17,7 +17,7 @@
 ;;; Copyright © 2017 André <eu@euandre.org>
 ;;; Copyright © 2017, 2018, 2020 Marius Bakke <mbakke@fastmail.com>
 ;;; Copyright © 2017 Stefan Reichör <stefan@xsteve.at>
-;;; Copyright © 2017 Oleg Pykhalov <go.wigust@gmail.com>
+;;; Copyright © 2017, 2020 Oleg Pykhalov <go.wigust@gmail.com>
 ;;; Copyright © 2018 Sou Bunnbu <iyzsong@member.fsf.org>
 ;;; Copyright © 2018 Christopher Baines <mail@cbaines.net>
 ;;; Copyright © 2018 Timothy Sample <samplet@ngyro.com>
@@ -55,6 +55,7 @@
   #:use-module (guix build-system cmake)
   #:use-module (guix build-system gnu)
   #:use-module (guix build-system go)
+  #:use-module (guix build-system perl)
   #:use-module (guix build-system python)
   #:use-module (guix build-system trivial)
   #:use-module (gnu packages apr)
@@ -632,6 +633,26 @@ indistinguishable from Git's.  You (or other contributors) can always fall back
 on @command{git}, and use any regular Git hosting service.")
     (license license:expat)))
 
+(define-public git-cal
+  (package
+    (name "git-cal")
+    (version "0.9.1")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url "https://github.com/k4rthik/git-cal")
+                    (commit (string-append "v" version))))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "08s9sif3qlk5n2dqpzq5yjczggnqlnxldljspjdqgpfydb2dqg3z"))))
+    (build-system perl-build-system)
+    (home-page "https://github.com/k4rthik/git-cal/")
+    (synopsis "GitHub like contributions calendar for terminal")
+    (description "@code{git-cal} is a script to view commits calendar similar
+to GitHub contributions calendar.")
+    (license license:expat)))
+
 (define-public libgit2
   (package
     (name "libgit2")