[ANCHOR-385]: Add documentation on how to pass JVM flags (#252)

docs/anchoring-assets/anchor-platform/getting_started.mdx

@@ -329,6 +329,37 @@ When making requests to the Platform API, add a JWT signed by the secret defined
 
 `PLATFORM_API_BASE_URL` uses `platform` instead of `localhost` as the host because you'll be making requests to the Platform API within the local network created by docker compose. When configuring your service in a staging or production environment, make sure to update your service urls.
 
+### Passing JVM flags
+
+Anchor Platform uses JVM to run. Sometimes, it's desired to change JVM flags to run the service. To do so, set environmental variable `JVM_FLAGS` to appropriate value
+
+```bash
+# dev.env
+JVM_FLAGS="-Xms256m -Xmx2048m"
+```
+
+:::tip
+
+If you need to pass environment variable from your machine to container, you should use `environment` compose option to set variables instead. Here's an example of using keystore from your local machine in the container:
+
+```yaml
+# docker-compose.yml
+version: "3.8"
+services:
+  sep-server:
+    image: stellar/anchor-platform:latest
+    command: --sep-server
+    env_file:
+      - ./dev.env
+    environment:
+      JVM_FLAGS: -Djavax.net.ssl.trustStore=/keystore.jks -Djavax.net.ssl.trustStorePassword=${KEYSTORE_PASSWORD}
+    volumes:
+      - ${KEYSTORE_LOCATION}:/keystore.jks
+# ...
+```
+
+Where `KEYSTORE_LOCATION` is local keystore location and `KEYSTORE_PASSWORD` is local keystore password. :::
+
 [sep-1]: https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0001.md
 [sep-9]: https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0009.md
 [sep-24]: https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0024.md