Add optional slimming instruction to README.md

Change-Id: I0321bacf2cb628dbdc8e0280cd311aee2e002e83
diff --git a/README.md b/README.md
index 63c55cb..8d9284f 100644
--- a/README.md
+++ b/README.md
@@ -126,14 +126,21 @@
 docker build -t ids-kl/derekovecs .
 ```
 
+### Optional: Slim down image using [Slim(toolkit)](https://github.com/slimtoolkit/slim)
+
+```bash
+slim build --new-expose=3000 --http-probe-ports=3000  --include-path /usr/local --mount $(pwd)/config:/config:z ids-kl/derekovecs
+```
+
+Will build an image `ids-kl/derekovecs.slim` reduced to ~25% of the original size.
+
 ### Copy configuration to make it mountable
 
 ```bash
 mkdir config
 cp example.conf config/derekovecs.conf
 ```
-
-### Run
+### Run docker image
 
 ``` bash
 docker run -d=false -p 3000:3000 --rm -v $(pwd)/config:/config:z ids-kl/derekovecs