README.md in riiif-1.4.4 vs README.md in riiif-1.5.0

@@ -61,10 +61,19 @@
 
 This file resolver caches the network files, so you will want to clear out the old files or the cache will expand until you run out of disk space.
 Using a script like this would be a good idea: https://github.com/pulibrary/loris/blob/607567b921404a15a2111fbd7123604f4fdec087/bin/loris-cache_clean.sh
 By default the cache is located in `tmp/network_files`. You can set the cache path like this: `Riiif::Image.file_resolver.cache_path = '/var/cache'`
 
+### GraphicsMagick
+
+To use [GraphicsMagick](http://www.graphicsmagick.org/) instead of ImageMagick
+
+    Riiif::ImagemagickCommandFactory.external_command = "gm convert"
+    Riiif::ImageMagickInfoExtractor.external_command  = "gm identify"
+
+You will of course need to install GraphicsMagick on your system.
+
 ## Usage
 
 Add the routes to your application by inserting the following line into `config/routes.rb`
 ```
   mount Riiif::Engine => '/image-service', as: 'riiif'
@@ -171,15 +180,15 @@
 # http://guides.rubyonrails.org/caching_with_rails.html#cache-stores
 Riiif::Engine.config.cache_duration_in_days = 30
 ```
 #### Special note for Passenger and Apache users
 If you are running riiif in Passenger under Apache, you must set the following in your virtual host definition:
- 
+
 ```
 AllowEncodedSlashes NoDecode
 ```
 
-You may also need to set the following in your virtual host definition, either at the top level, or within a 
+You may also need to set the following in your virtual host definition, either at the top level, or within a
 Location block for a specific path. See the [Passenger configuration reference](https://www.phusionpassenger.com/library/config/apache/reference/#passengerallowencodedslasheshttps://www.phusionpassenger.com/library/config/apache/reference/#passengerallowencodedslashes) for more info.
 
 ```
 PassengerAllowEncodedSlashes on
 ```