Doc : Add How to guide for Custom Property (#8209)

* Doc : Add How to guide for Custom Property

* Update the hostname

openmetadata-docs/content/how-to-guides/custom-properties.md

@@ -0,0 +1,145 @@
+---
+title: How to add a custom property to an entity
+slug: /how-to-guides/how-to-add-custom-property-to-an-entity
+---
+
+# How to add a custom property to an entity with API
+
+This tutorial will create a custom property for a `table` entity.
+
+Let's assume in your organization you want to keep track of table size, so to achieve that you will be creating a custom property for table entities and then providing a value to that property for each table.
+
+### Step 1: Get the table entity type.
+
+All OpenMetadata APIs are secured so make sure to add the proper headers.
+
+```commandline
+curl -X GET http://localhost:8585/api/v1/metadata/types/name/table
+```
+
+After the API call, you will get a response like this.
+
+```json
+{
+  "id": "7f0b032f-cdc8-4573-abb0-22165dcd8e07",
+  "name": "table",
+  "customProperties": [
+    {
+      "name": "tableSize",
+      "description": "Property for tracking the tableSize.",
+      "propertyType": {
+        "id": "7531f881-c37c-4e39-9154-4bdf0802e05e",
+        "type": "type",
+        "name": "string",
+        "fullyQualifiedName": "string",
+        "description": "\"A String type.\"",
+        "displayName": "string",
+        "href": "http://localhost:8585/api/v1/metadata/types/7531f881-c37c-4e39-9154-4bdf0802e05e"
+      }
+    }
+  ]
+}
+```
+
+Now take the `id` from above response `7f0b032f-cdc8-4573-abb0-22165dcd8e07`.
+
+### Step 2: Get the field types with `category=field`
+
+> From UI OpenMetadata only supports three field types
+>
+> - String
+> - Markdown
+> - Integer
+
+```commandline
+ curl -X GET http://localhost:8585/api/v1/metadata/types?category=field
+```
+
+This API will return all the available field types, for this tutorial grab the id of the `string` field type. i.e `7531f881-c37c-4e39-9154-4bdf0802e05e`
+
+### Step 3: Make a PUT call to create the custom property for the table entity
+
+```commandline
+curl -X PUT http://localhost:8585/api/v1/metadata/types/7f0b032f-cdc8-4573-abb0-22165dcd8e07
+```
+
+**Payload**
+
+```json
+{
+  "description": "Property for tracking the tableSize.",
+  "name": "tableSize",
+  "propertyType": {
+    "id": "7531f881-c37c-4e39-9154-4bdf0802e05e",
+    "type": "type"
+  }
+}
+```
+
+### Step 4: Get the custom properties for the table entity
+
+```commandline
+curl -X GET http://localhost:8585/api/v1/metadata/types/name/table?fields=customProperties
+```
+
+**Response**
+
+```json
+{
+  "id": "7f0b032f-cdc8-4573-abb0-22165dcd8e07",
+  "name": "table",
+  "customProperties": [
+    {
+      "name": "tableSize",
+      "description": "Property for tracking the tableSize.",
+      "propertyType": {
+        "id": "7531f881-c37c-4e39-9154-4bdf0802e05e",
+        "type": "type",
+        "name": "string",
+        "fullyQualifiedName": "string",
+        "description": "\"A String type.\"",
+        "displayName": "string",
+        "href": "http://localhost:8585/api/v1/metadata/types/7531f881-c37c-4e39-9154-4bdf0802e05e"
+      }
+    }
+  ]
+}
+```
+
+So for all table entities, we have `tableSize` custom property available now, let’s add the value for it for the `raw_product_catalog` table.
+
+### Step 5: Add/Edit the value of the custom property for the entity.
+
+All the custom properties value for the entity will be stored in the `extension` attribute.
+
+Let’s assume you have `raw_product_catalog` table and its id is `208598fc-bd5f-458c-bf98-59224e1620c7` so our PATCH API request will be like this.
+
+```commandline
+curl -X PATCH http://localhost:8585/api/v1/tables/208598fc-bd5f-458c-bf98-59224e1620c7
+```
+
+For the first time if we want to add the value to the custom property then the payload should be like this.
+
+```json
+[
+  {
+    "op": "add",
+    "path": "/extension",
+    "value": {
+      "tableSize": "50GB"
+    }
+  }
+]
+```
+
+When Changing the value of the custom property payload should be like this,
+
+```json
+[
+  {
+    "op": "replace",
+    "path": "/extension/tableSize",
+    "value": "60GB"
+  }
+]
+```

openmetadata-docs/content/menu.md

@@ -156,15 +156,15 @@ site_menu:
 
   - category: Deployment / Airflow
     url: /deployment/airflow
-    
+
   - category: Connectors
     url: /connectors
     color: violet-70
     icon: openmetadata
 
-  - category:  Connectors / Database
+  - category: Connectors / Database
     url: /connectors/database
-  - category:  Connectors / Database / Athena
+  - category: Connectors / Database / Athena
     url: /connectors/database/athena
   - category: Connectors / Database / Athena / Airflow
     url: /connectors/database/athena/airflow
@@ -483,7 +483,6 @@ site_menu:
   - category: Connectors / Ingestion / Run Connectors in your Airflow
     url: /connectors/ingestion/run-connectors-in-airflow
 
-
   - category: How to guides
     url: /how-to-guides
     color: violet-70
@@ -499,14 +498,14 @@ site_menu:
     url: /how-to-guides/teams-and-users
   - category: How to guides / Teams and Users / How to Organise Teams and Users
     url: /how-to-guides/teams-and-users/how-to-organise-teams-and-users
-
-
+  - category: How to guides / How to add a custom property to an entity
+    url: /how-to-guides/how-to-add-custom-property-to-an-entity
 
   - category: Features
     url: /openmetadata
     color: violet-70
     icon: openmetadata
-  
+
   - category: Features / Discovery & Collaboration
     url: /openmetadata/discovery-collaboration