Add colors!

Configuration-and-usage.md

@@ -46,7 +46,7 @@ If not specified otherwise than its mandatory item! Mandatory items are bold, op
 
 #### Example config file
 
-```
+```{.yml}
 worker-id: 1
 broker-uri: tcp://localhost:9657
 broker-ping-interval: 10  # milliseconds
@@ -147,7 +147,7 @@ Installation of **broker** program does following step to your computer:
 
 #### Example config file
 
-```
+```{.yml}
 # Address and port for clients (frontend)
 clients:
     address: "*"