Add readme explaining basic schema

README.md

+# iX Official Catalog
+
+A curated collection of TrueNAS SCALE enhanced Helm charts.
+
+## TrueNAS SCALE Chart Structure
+
+A TrueNAS SCALE chart repository differs slightly in directory structure from upstream repos in that it includes an `app version` directory.
+
+A TrueNAS SCALE chart also has three additional files an `app-readme.md` file that provides a high level overview display in the TrueNAS SCALE UI and a `questions.yaml` file defining questions to prompt the user with and an `item.yaml` file outlining item specific details. 
+
+There are 2 directories `charts` and `test`, each representing a train. Chart releases created from catalog items in a specific train cannot be moved to another train.
+
+```
+charts/ix-chart/<chart version>/
+  app-readme.md            # TrueNAS SCALE Specific: Readme file for display in TrueNAS SCALE UI
+  charts/                  # Directory containing dependency charts
+  Chart.yaml               # Required Helm chart information file
+  questions.yaml           # TrueNAS SCALE Specific: File containing questions for TrueNAS SCALE UI
+  README.md                # Optional: Helm Readme file (will be rendered in TrueNAS SCALE UI as well)
+  requirements.yaml        # Optional YAML file listing dependencies for the chart
+  templates/               # A directory of templates that, when combined with values.yml will generate K8s YAML
+  values.yaml              # The default configuration values for this chart
+```
+*See the upstream Helm chart [developer reference](https://helm.sh/docs/topics/chart_template_guide/) for a complete walk through of developing charts.*
+
+To convert an upstream chart to take advantage of TrueNAS SCALE enhanced UX, first create an `item.yaml` file.
+This file among other catalog item information provides a list of categories that this chart fits into. This helps users navigate and filtering when browsing the catalog UI.
+
+```
+$ cat charts/ix-chart/item.yaml
+categories:
+  - generic
+icon_url: "http://ix_url"
+```
+
+After that create `app-readme.md` file.
+
+```
+$ cat charts/ix-chart/<chart version>/app-readme.md
+
+# Wordpress ROCKS!
+```
+
+Then add a `questions.yaml` file to prompt the user for something.
+
+```
+groups:
+  - name: "Container Images"
+    description: "Image to be used for container"
+questions:
+  - variable: image
+    description: "Docker Image Details"
+    group: "Container Images"
+    schema:
+      type: dict
+      required: true
+      attrs:
+        - variable: repository
+          description: "Docker image repository"
+          label: "Image repository"
+          schema:
+            type: string
+            required: true
+        - variable: tag
+          description: "Tag to use for specified image"
+          label: "Image Tag"
+          schema:
+            type: string
+            default: "latest"
+        - variable: pullPolicy
+          description: "Docker Image Pull Policy"
+          label: "Image Pull Policy"
+          schema:
+            type: string
+            default: "IfNotPresent"
+            enum:
+              - "IfNotPresent"
+              - "Always"
+              - "Never"
+```
+
+The above will prompt the user with 2 text fields and a dropdown in the UI getting details for image configuration in a helm chart.
+
+#### Question Variable Reference
+
+| Variable  | Type | Required | Description |
+| ------------- | ------------- | --- |------------- |
+| 	variable                    | string        | true       |  define the variable name specified in the `values.yaml`file. |
+| 	label                       | string        | true       |  define the UI label. |
+| 	description                 | string        | false      |  specify the description of the variable. |
+| 	group                       | string        | false      |  group questions by input value. |
+| 	schema                      | dictionary    | true       |  specify schema details for the `variable` |
+| 	schema.type                 | string        | true       |  specify type of value for `variable` (current supported types are string, int, boolean, path, hostpath, list, dict, ipaddr, and cron).|
+| 	schema.required             | bool          | false      |  define if the variable is required or not (true \ false), defaults to false |
+| 	schema.default              | object        | false      |  specify the default value. |
+| 	schema.min_length           | int           | false      |  min character length for string type variable.|
+| 	schema.max_length           | int           | false      |  max character length for string type variable.|
+| 	schema.min                  | int           | false      |  min integer length. |
+| 	schema.max                  | int           | false      |  max integer length. |
+| 	schema.enum                 | []string      | false      |  specify the options when the variable type is `string`, for example, <br><br>enum:<br> - "RollingUpdate" <br> - "Recreate"|
+| 	schema.valid_chars          | string        | false      |  regular expression for input chars validation. |
+| 	schema.subquestions         | []subquestion | false      |  add an array of subquestions.|
+| 	schema.show_if              | string        | false      | show current variable if condition specified is true, for example `show_if: [["workloadType", "=", "CronJob"]]` |
+| 	schema.show_subquestions_if | string        | false      | show subquestions if is true or equal to one of the options. for example `show_subquestion_if: "static"`. system will convert this to the filters format specifid for `shcema.show_if` automatically.|
+| 	schema.attrs                | []variables   | false      | specified when `schema.type` is dictionary to declare attributes allowed in the dictionary. |
+| 	schema.items                | []variables   | false      | specified when `schema.type` is list to declare attributes allowed in the list. |
+
+**subquestions**: `subquestions[]` cannot contain `subquestions` or `show_subquestions_if` keys, but all other keys in the above table are supported. Also variables having `schema.type` list do not support `subquestions`.