Add sample config for slack-api

config.sample.yaml

@@ -108,3 +108,12 @@ services:
               Events: ["push", "issues"]
             "matrix-org/dendron":
               Events: ["pull_request"]
+
+  - ID: "slackapi_service"
+    Type: "slackapi"
+    UserID: "@slackapi:localhost" # requires a Syncing client
+    Config:
+      Hooks:
+        "hook1":
+          RoomID: "!someroom:id"
+          MessageType: "m.text" # default is m.text