gnu: Add r-ggally.

* gnu/packages/cran.scm (r-ggally): New variable.

gnu/packages/cran.scm

@@ -499,3 +499,34 @@ percentage, elapsed time, and/or the estimated completion time.  They work in
 terminals, in Emacs ESS, RStudio, Windows Rgui, and the macOS R.app.  The
 package also provides a C++ API, that works with or without Rcpp.")
     (license license:expat)))
+
+(define-public r-ggally
+  (package
+    (name "r-ggally")
+    (version "1.3.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (cran-uri "GGally" version))
+       (sha256
+        (base32
+         "12ddab0nd0f9c7bb6cx3c22mliyvc8xsxv26aqz3cvfbla8crp3b"))))
+    (properties `((upstream-name . "GGally")))
+    (build-system r-build-system)
+    (propagated-inputs
+     `(("r-ggplot2" ,r-ggplot2)
+       ("r-gtable" ,r-gtable)
+       ("r-plyr" ,r-plyr)
+       ("r-progress" ,r-progress)
+       ("r-rcolorbrewer" ,r-rcolorbrewer)
+       ("r-reshape" ,r-reshape)))
+    (home-page "https://ggobi.github.io/ggally")
+    (synopsis "Extension to ggplot2")
+    (description
+     "The R package ggplot2 is a plotting system based on the grammar of
+graphics.  GGally extends ggplot2 by adding several functions to reduce the
+complexity of combining geometric objects with transformed data.  Some of
+these functions include a pairwise plot matrix, a two group pairwise plot
+matrix, a parallel coordinates plot, a survival plot, and several functions to
+plot networks.")
+    (license license:gpl2+)))