Cm Subscriptions Docs

- Included documentation for an overview of Cm Data Subscription for the
  Create and Delete use case.
- Only included the json schemas for the events that are coming in and
  going out of NCMP.
- Not mentioning anything abt the internal events we use between DMIs.
- The docs can later be used to explain abt the notifications when they
  are implemented.

Issue-ID: CPS-2324
Change-Id: I2497656e0e56c93054b7e92b1742a668463c3ffc
Signed-off-by: mpriyank <priyank.maheshwari@est.tech>
diff --git a/docs/schemas/ncmp-in-event-schema-1.0.0.json b/docs/schemas/ncmp-in-event-schema-1.0.0.json
new file mode 100644
index 0000000..f8b6c2e
--- /dev/null
+++ b/docs/schemas/ncmp-in-event-schema-1.0.0.json
@@ -0,0 +1,73 @@
+{
+  "$id": "urn:cps:org.onap.cps.ncmp.events:cm-notification-subscription-ncmp-in-event:1.0.0",
+  "$ref": "#/definitions/NcmpInEvent",
+  "$schema": "https://json-schema.org/draft/2019-09/schema",
+  "definitions": {
+    "NcmpInEvent": {
+      "description": "The payload for subscription merge event.",
+      "javaType": "org.onap.cps.ncmp.impl.cmnotificationsubscription_1_0_0.client_to_ncmp.NcmpInEvent",
+      "properties": {
+        "data": {
+          "properties": {
+            "subscriptionId": {
+              "description": "The subscription details.",
+              "type": "string"
+            },
+            "predicates": {
+              "type": "array",
+              "description": "Additional values to be added into the subscription",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "targetFilter": {
+                    "description": "CM Handles to be targeted by the subscription",
+                    "type": "array",
+                    "items": {
+                      "type": "string"
+                    }
+                  },
+                  "scopeFilter": {
+                    "type": "object",
+                    "properties": {
+                      "datastore": {
+                        "description": "Datastore which is to be used by the subscription",
+                        "type": "string",
+                        "enum": ["ncmp-datastore:passthrough-operational", "ncmp-datastore:passthrough-running"]
+                      },
+                      "xpathFilter": {
+                        "description": "Filter to be applied to the CM Handles through this event",
+                        "type": "array",
+                        "items": {
+                          "type": "string"
+                        }
+                      }
+                    },
+                    "additionalProperties": false,
+                    "required": [
+                      "xpathFilter"
+                    ]
+                  }
+                },
+                "additionalProperties": false,
+                "required": [
+                  "targetFilter"
+                ]
+              },
+              "additionalProperties": false
+            }
+          },
+          "required": [
+            "subscriptionId"
+          ],
+          "type": "object",
+          "additionalProperties": false
+        }
+      },
+      "type": "object",
+      "additionalProperties": false,
+      "required": [
+        "data"
+      ]
+    }
+  }
+}
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