Validate application settings only if column exists

app/models/application_setting.rb

 class ApplicationSetting < ActiveRecord::Base
   validates :home_page_url, allow_blank: true,
-    format: { with: URI::regexp(%w(http https)), message: "should be a valid url" }
+    format: { with: URI::regexp(%w(http https)), message: "should be a valid url" },
+    if: :home_page_url_column_exist
   def self.current
     ApplicationSetting.last
@@ -15,4 +16,8 @@ class ApplicationSetting < ActiveRecord::Base
       sign_in_text: Settings.extra['sign_in_text'],
     )
   end
+
+  def home_page_url_column_exist
+    ActiveRecord::Base.connection.column_exists?(:application_settings, :home_page_url)
+  end
 end

db/schema.rb

@@ -424,7 +424,6 @@ ActiveRecord::Schema.define(version: 20150116234544) do
     t.integer  "notification_level",       default: 1,     null: false
     t.datetime "password_expires_at"
     t.integer  "created_by_id"
-    t.datetime "last_credential_check_at"
     t.string   "avatar"
     t.string   "confirmation_token"
     t.datetime "confirmed_at"
@@ -432,6 +431,7 @@ ActiveRecord::Schema.define(version: 20150116234544) do
     t.string   "unconfirmed_email"
     t.boolean  "hide_no_ssh_key",          default: false
     t.string   "website_url",              default: "",    null: false
+    t.datetime "last_credential_check_at"
     t.string   "github_access_token"
   end