doc: Add a basic example for managfing oneshot jobs

Resolves #49

README.md

@@ -149,6 +149,7 @@ A few rules to clear up this ambiguity:
 - Relative paths referenced on the command line are relative to the current working directory the user is in
 
 For additional context, take a look at [paths examples](PATHS.md)
+
 ## Labels Overview
 A selector can be used to only target a subset of releases when running helmfile. This is useful for large helmfiles with releases that are logically grouped together.
 
@@ -159,3 +160,7 @@ Multiple labels can be specified using `,` as a separator. A release must match
 The `selector` parameter can be specified multiple times. Each parameter is resolved independently so a release that matches any parameter will be used. 
 
 `--selector tier=frontend --selector tier=backend` will select all the charts
+
+## Examples
+
+For more examples, see [examples/REAMDME.md](https://github.com/roboll/helmfile/blob/master/examples/README.md).

examples/README.md

@@ -0,0 +1,35 @@
+# Helmfile practical examples and advanced usages
+
+## Managing oneshot-jobs with Helmfile
+
+In case you want to manage oneshot-jobs like a report generation or a database migration and so on, add a dedicated release spec for the job in `helmfile.yaml` like:
+
+```yaml
+repositories:
+  - name: yourorg
+    url: https://yourorg.example.com/charts
+
+releases:
+  - name: dbmigrator
+    labels:
+      job: dbmigrator
+    chart: ./dbmigrator
+    # DB host, port, and connection opts for the environment
+    values:
+    - "deploy/environments/{{ env "RAILS_ENV" }}/values.yaml"
+    # DB username and password encrypted with helm-secrets(mozilla/sops)
+    secrets:
+    - "deploy/environments/{{ env "RAILS_ENV" }}/secrets.yaml"
+```
+
+You would then start a database migration job by executing:
+
+```console
+# Start a database migration for the prod environment
+$ RAILS_ENV=prod helmfile sync --selector job=dbmigrator
+
+# Tail log until you are satisfied
+$ kubectl logs -l job=dbmigrator
+```
+
+For more context, see [this issue](https://github.com/roboll/helmfile/issues/49).