[SPARK-11407][SPARKR] Add doc for running from RStudio

![image](https://cloud.githubusercontent.com/assets/8969467/10871746/612ba44a-80a4-11e5-99a0-40b9931dee52.png)
(This is without css, but you get the idea)
shivaram

Author: felixcheung <[email protected]>

Closes apache#9401 from felixcheung/rstudioprogrammingguide.

docs/sparkr.md

@@ -30,24 +30,64 @@ The entry point into SparkR is the `SparkContext` which connects your R program
 You can create a `SparkContext` using `sparkR.init` and pass in options such as the application name
 , any spark packages depended on, etc. Further, to work with DataFrames we will need a `SQLContext`,
 which can be created from the  SparkContext. If you are working from the `sparkR` shell, the
-`SQLContext` and `SparkContext` should already be created for you.
+`SQLContext` and `SparkContext` should already be created for you, and you would not need to call
+`sparkR.init`.
 
+<div data-lang="r" markdown="1">
 {% highlight r %}
 sc <- sparkR.init()
 sqlContext <- sparkRSQL.init(sc)
 {% endhighlight %}
+</div>
+
+## Starting Up from RStudio
 
-In the event you are creating `SparkContext` instead of using `sparkR` shell or `spark-submit`, you 
+You can also start SparkR from RStudio. You can connect your R program to a Spark cluster from
+RStudio, R shell, Rscript or other R IDEs. To start, make sure SPARK_HOME is set in environment
+(you can check [Sys.getenv](https://stat.ethz.ch/R-manual/R-devel/library/base/html/Sys.getenv.html)),
+load the SparkR package, and call `sparkR.init` as below. In addition to calling `sparkR.init`, you
 could also specify certain Spark driver properties. Normally these
 [Application properties](configuration.html#application-properties) and
 [Runtime Environment](configuration.html#runtime-environment) cannot be set programmatically, as the
 driver JVM process would have been started, in this case SparkR takes care of this for you. To set
 them, pass them as you would other configuration properties in the `sparkEnvir` argument to
 `sparkR.init()`.
 
+<div data-lang="r" markdown="1">
 {% highlight r %}
-sc <- sparkR.init("local[*]", "SparkR", "/home/spark", list(spark.driver.memory="2g"))
+if (nchar(Sys.getenv("SPARK_HOME")) < 1) {
+  Sys.setenv(SPARK_HOME = "/home/spark")
+}
+library(SparkR, lib.loc = c(file.path(Sys.getenv("SPARK_HOME"), "R", "lib")))
+sc <- sparkR.init(master = "local[*]", sparkEnvir = list(spark.driver.memory="2g"))
 {% endhighlight %}
+</div>
+
+The following options can be set in `sparkEnvir` with `sparkR.init` from RStudio:
+
+<table class="table">
+  <tr><th>Property Name</th><th>Property group</th><th><code>spark-submit</code> equivalent</th></tr>
+  <tr>
+    <td><code>spark.driver.memory</code></td>
+    <td>Application Properties</td>
+    <td><code>--driver-memory</code></td>
+  </tr>
+  <tr>
+    <td><code>spark.driver.extraClassPath</code></td>
+    <td>Runtime Environment</td>
+    <td><code>--driver-class-path</code></td>
+  </tr>
+  <tr>
+    <td><code>spark.driver.extraJavaOptions</code></td>
+    <td>Runtime Environment</td>
+    <td><code>--driver-java-options</code></td>
+  </tr>
+  <tr>
+    <td><code>spark.driver.extraLibraryPath</code></td>
+    <td>Runtime Environment</td>
+    <td><code>--driver-library-path</code></td>
+  </tr>
+</table>
 
 </div>