Add option to configure feed items displayed in homepage

db/migrate/20180519132610_create_widget_feeds.rb

@@ -2,6 +2,7 @@ class CreateWidgetFeeds < ActiveRecord::Migration
   def change
     create_table :widget_feeds do |t|
       t.string :kind
+      t.integer :limit, default: 3
       t.timestamps null: false
     end
   end

db/schema.rb

@@ -1236,8 +1236,9 @@ ActiveRecord::Schema.define(version: 20180519132610) do
 
   create_table "widget_feeds", force: :cascade do |t|
     t.string   "kind"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
+    t.integer  "limit",      default: 3
+    t.datetime "created_at",             null: false
+    t.datetime "updated_at",             null: false
   end
 
   add_foreign_key "administrators", "users"