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

db/migrate/20170119214911_create_preview_cards.rb

@@ -0,0 +1,17 @@
+class CreatePreviewCards < ActiveRecord::Migration[5.0]
+  def change
+    create_table :preview_cards do |t|
+      t.integer :status_id
+      t.string :url, null: false, default: ''
+
+      # OpenGraph
+      t.string :title, null: true
+      t.string :description, null: true
+      t.attachment :image
+
+      t.timestamps
+    end
+
+    add_index :preview_cards, :status_id, unique: true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170114203041) do
+ActiveRecord::Schema.define(version: 20170119214911) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -157,6 +157,20 @@ ActiveRecord::Schema.define(version: 20170114203041) do
     t.index ["uid"], name: "index_oauth_applications_on_uid", unique: true, using: :btree
   end
 
+  create_table "preview_cards", force: :cascade do |t|
+    t.integer  "status_id"
+    t.string   "url",                default: "", null: false
+    t.string   "title"
+    t.string   "description"
+    t.string   "image_file_name"
+    t.string   "image_content_type"
+    t.integer  "image_file_size"
+    t.datetime "image_updated_at"
+    t.datetime "created_at",                      null: false
+    t.datetime "updated_at",                      null: false
+    t.index ["status_id"], name: "index_preview_cards_on_status_id", unique: true, using: :btree
+  end
+
   create_table "pubsubhubbub_subscriptions", force: :cascade do |t|
     t.string   "topic",      default: "",    null: false
     t.string   "callback",   default: "",    null: false