Add API support for setting status content-type

app/controllers/api/v1/statuses_controller.rb

@@ -54,6 +54,7 @@ class Api::V1::StatusesController < Api::BaseController
                                          scheduled_at: status_params[:scheduled_at],
                                          application: doorkeeper_token.application,
                                          poll: status_params[:poll],
+                                         content_type: status_params[:content_type],
                                          idempotency: request.headers['Idempotency-Key'])
 
     render json: @status, serializer: @status.is_a?(ScheduledStatus) ? REST::ScheduledStatusSerializer : REST::StatusSerializer
@@ -85,6 +86,7 @@ class Api::V1::StatusesController < Api::BaseController
       :spoiler_text,
       :visibility,
       :scheduled_at,
+      :content_type,
       media_ids: [],
       poll: [
         :multiple,