Use frozen_string_literal comment

config/app.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'logger'
 require 'pathname'
 

lib/api.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'sinatra'
 require 'sinatra/cross_origin'
 require 'sinatra/jsonp'

lib/currency.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Currency < Sequel::Model
   dataset_module do
     def recent

lib/quote.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'virtus'
 require 'currency'
 

lib/tasks/db.rake

@@ -1,4 +1,9 @@
 namespace :db do
+  desc 'Create db'
+  task :create do
+    `createdb fixer`
+  end
+
   desc 'Run database migrations'
   task migrate: :environment do
     Sequel.extension(:migration)