Fix #463 - Fetch and display previews of URLs using OpenGraph tags

app/models/preview_card.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class PreviewCard < ApplicationRecord
+  IMAGE_MIME_TYPES = ['image/jpeg', 'image/png', 'image/gif'].freeze
+
+  belongs_to :status
+
+  has_attached_file :image, styles: { original: '120x120#' }, convert_options: { all: '-quality 80 -strip' }
+
+  validates :url, presence: true
+  validates_attachment_content_type :image, content_type: IMAGE_MIME_TYPES
+  validates_attachment_size :image, less_than: 1.megabytes
+
+  def save_with_optional_image!
+    save!
+  rescue ActiveRecord::RecordInvalid
+    self.image = nil
+    save!
+  end
+end