add readme info

README.md

@@ -26,7 +26,7 @@
 
 Converting a Seurat object to a Loupe file is as simple as the following:
 
-```R
+```r
 # import the library
 library("loupeR")
 
@@ -36,7 +36,7 @@ create_loupe_from_seurat(seurat_obj)
 
 Use the function `create_loupe` if you need more control in the clusters and projections that included in the Loupe file.
 
-```R
+```r
 # import the library
 library("loupeR")
 
@@ -56,7 +56,7 @@ create_loupe(
 
 Additionally, use the utility function `read_feature_ids_from_tsv` to read the Ensemble ids from the 10x dataset. A Seurat object will only have imported the feature names or ids and attached these as rownames to the count matrix. In order for the Ensemble id links to work correctly within Loupe Browser, one must manually import them and include them.
 
-```R
+```r
 # import the library
 library("loupeR")
 
@@ -106,6 +106,10 @@ loupeR::setup()
 
 If you are interested in automating LoupeR installation and execution (and are blocked by interactive license acceptance), please write to [[email protected]](mailto:[email protected]) for further assistance.
 
+### Customizing the user data directory
+
+By default the louper executable, which is the binary that understands and creates Loupe files, will be stored in the systems `tools::R_user_dir`.  You can update this path by setting the environment variable `LOUPER_USER_DATA_DIR` to a directory of your choosing.
+
 ## Loupe Browser Compatibility
 
 With new versions of the Loupe Browser, new version of LoupeR need to be released. The table below shows version requirements between the two.
@@ -159,7 +163,7 @@ For more in depth documentation and support please head to our [support page](ht
 
 Additionally, we have provided utility functions to help gather useful information when contacting support or creating a Github issue.
 
-```R
+```r
 # import the library
 library("loupeR")