add what about dash section

.circleci/config.yml

@@ -27,7 +27,7 @@ jobs:
             sudo apt-get install -y pandoc libudunits2-dev libgdal-dev libxt-dev libglu1-mesa-dev libfftw3-dev
             sudo R -e 'install.packages(c("curl", "devtools", "mvtnorm")); devtools::install_github("hypertidy/anglr"); devtools::install_github("johannesbjork/LaCroixColoR"); devtools::install_github("ropensci/plotly"); install.packages("BiocManager"); BiocManager::install("EBImage"); devtools::install_deps(dependencies = TRUE) '
       - save_cache:
-          key: cache3
+          key: cache4
           paths:
             - "/usr/local/lib/R/site-library"
       - store_artifacts:
@@ -41,8 +41,8 @@ jobs:
             mkdir build
             mkdir build/ggplot2
             mkdir build/r
-            for i in r/*.Rmd; do Rscript -e "rmarkdown::render('$i', output_dir='build/r')"; done
-            for i in ggplot2/*.Rmd; do Rscript -e "rmarkdown::render('$i', output_dir='build/ggplot2')"; done
+            for i in r/*.Rmd; do cat what-about-dash.md >> $i; Rscript -e "rmarkdown::render('$i', output_dir='build/r')"; done
+            for i in ggplot2/*.Rmd; do cat what-about-dash.md >> $i; Rscript -e "rmarkdown::render('$i', output_dir='build/ggplot2')"; done
             python3 -m venv venv
             . venv/bin/activate
             pip3 install python-frontmatter

what-about-dash.md

@@ -0,0 +1,31 @@
+
+### What About Dash?
+
+[Dash for R](https://dashr.plot.ly/) is an open-source framework for building analytical applications, with no Javascript required, and it is tightly integrated with the Plotly graphing library. 
+
+Learn about how to install Dash for R at https://dashr.plot.ly/installation.
+
+Everywhere in this page that you see `fig`, you can display the same figure in a Dash for R application by passing it to the `figure` argument of the [`Graph` component](https://dashr.plot.ly/dash-core-components/graph) from the built-in `dashCoreComponents` package like this:
+
+```{r eval=FALSE}
+library(plotly)
+
+fig <- plot_ly() 
+# fig <- fig %>% add_trace( ... )
+# fig <- fig %>% layout( ... ) 
+
+library(dash)
+library(dashCoreComponents)
+library(dashHtmlComponents)
+
+app <- Dash$new()
+app$layout(
+    htmlDiv(
+        list(
+                dccGraph(figure=fig) 
+        )
+     )
+)
+
+app$run_server(debug=TRUE, dev_tools_hot_reload=FALSE)
+```