Merge pull request #423 from permitio/update-java-sdk-page

update java sdk page

docs/sdk/java/user/create.mdx

@@ -15,7 +15,7 @@ You will later pass this ID to the `permit.check()` API. You can use anything fo
 `first_name` - **optional** - First name of the user.<br/>
 `last_name` - **optional** - Last name of the user.<br/>
 `attributes` - **optional** - Arbitraty user attributes that will be used to enforce attribute-based access control policies.<br/>
-
+`role_assignments` - **optional**  - List of roles to assign to the user in the environment.<br/>
 
 ### Implementation
 
@@ -36,3 +36,28 @@ UserRead user = permit.api.users.create(
         .withAttributes(userAttributes)
 );
 ```
+
+### Implementation(with roles assignment)
+
+```java
+import io.permit.sdk.openapi.models.UserCreate;
+import io.permit.sdk.openapi.models.UserRead;
+
+// optional attributes for attribute-based access control
+HashMap<String, Object> userAttributes = new HashMap<>();
+userAttributes.put("age", Integer.valueOf(50));
+userAttributes.put("fav_color", "red");
+
+final List<UserRoleCreate> roleAssignments = Arrays.asList(
+                new UserRoleCreate("editor", "default")
+        );
+
+UserRead user = permit.api.users.create(
+    (new UserCreate("auth0|elon"))
+        .withEmail("elonmusk@tesla.com")
+        .withFirstName("Elon")
+        .withLastName("Musk")
+        .withAttributes(userAttributes)
+        .withRoleAssignments(roleAssignments);
+);
+```