add link to community thread that inspired example

cpsievert · cpsievert · commit 38c03e4d66e2 · 2019-02-21T15:53:25.000-06:00
diff --git a/inst/examples/shiny/drag_lines/app.R b/inst/examples/shiny/drag_lines/app.R
@@ -1,3 +1,4 @@
+# see https://community.rstudio.com/t/sliding-a-point-on-a-plot-rather-than-sliderinput-to-update-plot-in-shiny/16405/7
 library(shiny)
 library(plotly)
 

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+# see https://community.rstudio.com/t/sliding-a-point-on-a-plot-rather-than-sliderinput-to-update-plot-in-shiny/16405/7`
`1`	`2`	`library(shiny)`
`2`	`3`	`library(plotly)`
`3`	`4`