Document operators

Signed-off-by: Eric Lippmann <eric.lippmann@icinga.com>

README.md

@@ -31,6 +31,7 @@ Documentation
 * [Create your first process node](doc/04-Create-your-first-process-node.md)
 * [Importing Processes](doc/05-Importing-Processes.md)
 * [Customize Node Order](doc/06-Customize-Node-Order.md)
+* [Operators](doc/09-Operators.md)
 
 ### Web Components
 * [Breadcrumb](doc/12-Web-Components-Breadcrumb.md)

doc/09-Operators.md

@@ -0,0 +1,24 @@
+# Operators <a id="operators">
+
+Every Business Process requires an Operator. This operator defines its behaviour and specifies how its very own state is
+going to be calculated.
+
+## AND <a id="and-operator">
+
+The `AND` operator selects the **WORST** state of its child nodes:
+
+![And Operator](screenshot/09_operators/0901_and-operator.png)
+
+## AND <a id="or-operator">
+
+The `OR` operator selects the **BEST** state of its child nodes:
+
+![Or Operator](screenshot/09_operators/0902_or-operator.png)
+
+![Or Operator #2](screenshot/09_operators/0903_or-operator-without-ok.png)
+
+## MIN n <a id="min-operator">
+
+The `MIN` operator selects the **WORST** state out of the **BEST n** child node states:
+
+![MIN](screenshot/09_operators/0904_min-operator.png)