Restore and update the configuration doc (#455)

* Create configuration.md

docs/configuration.md

@@ -0,0 +1,106 @@
+
+# Configuring Infra
+
+* [Overview](#overview)
+* [Create a configuration file](#create-a-configuration-file)
+* [Full Example](#full-example)
+* [Reference](#reference)
+  * [`sources`](#sources)
+  * [`groups`](#groups)
+  * [`users`](#users)
+  * [`roles`](#roles)
+  * [`destinations`](#destinations)
+
+## Overview
+
+For teams who require configuration to be stored in version control, Infra can be managed via a configuration file, `infra.yaml`.
+
+## Create a configuration file
+
+First, create a config file `infra.yaml`:
+
+```
+sources:
+  - type: okta
+    domain: acme.okta.com
+    clientId: 0oapn0qwiQPiMIyR35d6
+    clientSecret: infra-registry-okta/clientSecret
+    apiToken: infra-registry-okta/apiToken
+
+groups:
+  - name: administrators
+    source: okta
+    roles:
+      - name: cluster-admin
+        kind: cluster-role
+        destinations:
+          - name: my-first-destination
+```
+
+Then, apply it to the Infra Registry:
+
+```
+helm upgrade infra-registry infrahq/registry -n infrahq --set-file config=./infra.yaml
+```
+
+## Full Example
+
+```yaml
+sources:
+  - type: okta
+    domain: acme.okta.com
+    clientId: 0oapn0qwiQPiMIyR35d6
+    clientSecret: infra-registry-okta/clientSecret
+    apiToken: infra-registry-okta/apiToken
+
+groups:
+  - name: administrators
+    source: okta
+    roles:
+      - name: cluster-admin
+        kind: cluster-role
+        destinations:
+          - name: my-first-destination
+
+users:
+  - email: manager@example.com
+    roles:
+      - name: view
+        kind: cluster-role
+        destinations:
+          - name: my-first-destination
+            namespaces: 
+              - infrahq
+              - development
+          - name: cluster-BBB
+  - email: developer@example.com
+    roles:
+      - name: writer
+        kind: role
+        destinations:
+          - name: my-first-destination
+            namespaces:
+              - development
+```
+
+## Reference
+
+### `sources`
+
+A list of sources to sync and authenticate users from
+
+### `groups`
+
+A list of groups from identity providers for which to specify roles
+
+### `users`
+
+A list of users from identity providers for which to specify roles
+
+### `roles`
+
+`roles` is a list of role mappings to Kubernetes roles
+
+### `destinations`
+
+A list of Kubernetes clusters a role mapping applies to