Add API to upload media attachments

db/migrate/20160905150353_create_media_attachments.rb

@@ -0,0 +1,14 @@
+class CreateMediaAttachments < ActiveRecord::Migration[5.0]
+  def change
+    create_table :media_attachments do |t|
+      t.integer :status_id, null: true, default: nil
+      t.attachment :file
+      t.string :remote_url, null: false, default: ''
+      t.integer :account_id
+
+      t.timestamps
+    end
+
+    add_index :media_attachments, :status_id
+  end
+end