Add API to upload media attachments

app/controllers/api/media_controller.rb

@@ -0,0 +1,8 @@
+class Api::MediaController < ApiController
+  before_action :doorkeeper_authorize!
+  respond_to    :json
+
+  def create
+    @media = MediaAttachment.create!(account: current_user.account, file: params[:file])
+  end
+end