adding curl command example

Author: idalithb

website/src/pages/en/subgraphs/querying/managing-api-keys.mdx

@@ -48,6 +48,16 @@ When you query The Graph from your dapp, you can use your API key in two ways:
    Authorization: Bearer <YOUR_API_KEY>
    ```
 
+   Curl command example:
+
+   ```
+   curl -X POST \
+   -H "Content-Type: application/json" \
+   -H "Authorization: Bearer {api-key}" \
+   -d '{"query": "{ graphNetworks(first: 5) { id controller graphToken epochManager } graphAccounts(first: 5) { id names { id } defaultName { id } createdAt } }", "operationName": "Subgraphs", "variables": {}}' \
+   https://gateway.thegraph.com/api/subgraphs/id/DZz4kDTdmzWLWsV373w2bSmoar3umKKH9y82SUKr5qmp
+   ```
+
 Check out [Querying from an App](/subgraphs/querying/from-an-application) for more details.
 
 ## Manage API Keys