Update README.

README.md

@@ -13,8 +13,22 @@ It's like a unit test for your documentation.
 
 To use simple, run it from the command line providing the directory the documentation files reside in. Example:
 
+To generate the default configuration file, run init:
+
+```sh
+simple init
+```
+
+Then you can just run it:
+
 ```sh
-simple -d ./docs/
+simple
+```
+
+or specify a specific directory:
+
+```sh
+simple -f./docs/
 ```
 
 To get a full list of options and flags, run the help command:
@@ -23,10 +37,32 @@ To get a full list of options and flags, run the help command:
 simple help
 ```
 
+### In CI
+
+In CI, it is recommended to run it like so:
+
+```sh
+simple --no-color --no-progress-bar --report-file=report.junit.xml
+```
+
+This will force a junit report to be generated, for use in your CI reporting system.
+
 ## Installation
 
 Simple can either be installed as an executable PHAR, or as a composer dependency.
 
+Alternatively, it can be used with docker for CI builds or locally.
+
+### Docker:
+
+The docker image is: `marisa50/simple`.
+
+To run simple on your docs:
+
+```sh
+docker run --rm --interactive --tty --volume $PWD:/app m50/simple:latest
+```
+
 ### Phar:
 
 ```sh