feat: Add Platform APIs (#1456)

app/controllers/platform/api/v1/account_users_controller.rb

@@ -0,0 +1,29 @@
+class Platform::Api::V1::AccountUsersController < PlatformController
+  before_action :set_resource
+  before_action :validate_platform_app_permissible
+
+  def index
+    render json: @resource.account_users
+  end
+
+  def create
+    @account_user = @resource.account_users.find_or_initialize_by(user_id: account_user_params[:user_id])
+    @account_user.update!(account_user_params)
+    render json: @account_user
+  end
+
+  def destroy
+    @resource.account_users.find_by(user_id: account_user_params[:user_id])&.destroy
+    head :ok
+  end
+
+  private
+
+  def set_resource
+    @resource = Account.find(params[:account_id])
+  end
+
+  def account_user_params
+    params.permit(:user_id, :role)
+  end
+end