Added Installing section

Author: willmcgugan

README.md

@@ -6,6 +6,13 @@ Amazon S3 cloud storage.
 As a PyFilesystem concrete class, [S3FS](http://fs-s3fs.readthedocs.io/en/latest/) allows you to work with S3 in the
 same way as any other supported filesystem.
 
+## Installing
+
+You can install S3FS from pip as follows:
+
+```
+pip install fs-s3fs
+```
 
 ## Opening a S3FS