Add some documentation

Author: holdenk

docs/sparkr.md

@@ -27,9 +27,9 @@ All of the examples on this page use sample data included in R or the Spark dist
 <div data-lang="r"  markdown="1">
 The entry point into SparkR is the `SparkContext` which connects your R program to a Spark cluster.
 You can create a `SparkContext` using `sparkR.init` and pass in options such as the application name
-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.
+, 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.
 
 {% highlight r %}
 sc <- sparkR.init()
@@ -62,7 +62,9 @@ head(df)
 
 SparkR supports operating on a variety of data sources through the `DataFrame` interface. This section describes the general methods for loading and saving data using Data Sources. You can check the Spark SQL programming guide for more [specific options](sql-programming-guide.html#manually-specifying-options) that are available for the built-in data sources.
 
-The general method for creating DataFrames from data sources is `read.df`. This method takes in the `SQLContext`, the path for the file to load and the type of data source. SparkR supports reading JSON and Parquet files natively and through [Spark Packages](http://spark-packages.org/) you can find data source connectors for popular file formats like [CSV](http://spark-packages.org/package/databricks/spark-csv) and [Avro](http://spark-packages.org/package/databricks/spark-avro).
+The general method for creating DataFrames from data sources is `read.df`. This method takes in the `SQLContext`, the path for the file to load and the type of data source. SparkR supports reading JSON and Parquet files natively and through [Spark Packages](http://spark-packages.org/) you can find data source connectors for popular file formats like [CSV](http://spark-packages.org/package/databricks/spark-csv) and [Avro](http://spark-packages.org/package/databricks/spark-avro). These packages can either be added by
+specifying `--packages` with `sparm-submit` or `sparkR` commands, or if creating context through `init`
+you can specify the packages with the `packages` argument.
 
 We can see how to use data sources using an example JSON input file. Note that the file that is used here is _not_ a typical JSON file. Each line in the file must contain a separate, self-contained valid JSON object. As a consequence, a regular multi-line JSON file will most often fail.