[DOC] Update R doc

doc/R-package/Makefile

@@ -0,0 +1,14 @@
+# This is the makefile for compiling Rmarkdown files into the md file with results.
+PKGROOT=../../R-package
+
+# ADD The Markdown to be built here, with suffix md
+discoverYourData.md: $(PKGROOT)/vignettes/discoverYourData.Rmd
+xgboostPresentation.md: $(PKGROOT)/vignettes/xgboostPresentation.Rmd
+
+# General Rules for build rmarkdowns, need knitr
+%.md:
+	Rscript -e \
+	"require(knitr);"\
+	"knitr::opts_knit\$$set(root.dir=\".\");"\
+	"knitr::opts_chunk\$$set(fig.path=\"../web-data/xgboost/knitr/$(basename $@)-\");"\
+	"knitr::knit(\"$+\")"