Merge pull request #194 from jrjohnson/service-docs

[Doc] Add information on creating and configuring checks

README.md

@@ -84,6 +84,9 @@ liip_monitor:
 
 ## Adding Health Checks ##
 
+See [Writing Custom Checks](https://docs.zendframework.com/zend-diagnostics/custom-checks/) for instructions
+on creating a custom check.
+
 Once you implemented the class then it's time to register the check service with our service container:
 
 ```yml
@@ -103,6 +106,9 @@ as long as the service is properly tagged. The ``alias`` is optional and will th
 define the ``id`` used when running health checks individually, otherwise the full service
 id must be used in this case.
 
+If your app's service definition is using `autoconfigure` to discover services then classes 
+which implement `ZendDiagnostics\Check\CheckInterface` will be tagged automatically.
+
 ## Available Built-in Health Checks ##
 
 See "Full Default Config" below for a list of all built-in checks and their configuration.
@@ -226,6 +232,17 @@ services:
             - { name: liip_monitor.check, alias: php_extensions, group: app_server }
 ```
 
+`autoconfigure` will place checks into the default group. You must add `autoconfigure: false` to the service
+definition to change the group:
+
+```yml
+services:
+    Acme\HelloBundle\Check\PhpExtensionsCheck:
+        autoconfigure: false
+        tags:
+            - { name: liip_monitor.check, group: app_server }
+```
+
 ### Specify group for CLI commands
 
 Both CLI commands have a `--group=...` option. If it is not given, the default group is used.