Add "secrets tune" command documentation

website/source/docs/commands/secrets/tune.html.md

@@ -0,0 +1,38 @@
+---
+layout: "docs"
+page_title: "secrets tune - Command"
+sidebar_current: "docs-commands-secrets-tune"
+description: |-
+  The "secrets tune" command tunes the configuration options for the secrets
+  engine at the given PATH. The argument corresponds to the PATH where the
+  secrets engine is enabled, not the TYPE!
+---
+
+# secrets tune
+
+The `secrets tune` command tunes the configuration options for the secrets
+engine at the given PATH. The argument corresponds to the PATH where the secrets
+engine is enabled, not the TYPE!
+
+## Examples
+
+Tune the default lease for the PKI secrets engine:
+
+```text
+$ vault secrets tune -default-lease-ttl=72h pki/
+```
+
+## Usage
+
+The following flags are available in addition to the [standard set of
+flags](/docs/commands/index.html) included on all commands.
+
+- `-default-lease-ttl` `(duration: "")` - The default lease TTL for this secrets
+  engine. If unspecified, this defaults to the Vault server's globally
+  configured default lease TTL, or a previously configured value for the secrets
+  engine.
+
+- `-max-lease-ttl` `(duration: "")` - The maximum lease TTL for this secrets
+  engine. If unspecified, this defaults to the Vault server's globally
+  configured maximum lease TTL, or a previously configured value for the secrets
+  engine.