diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 0fdd562..f213f4e 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2016-08-30 11:24:51 -0400 using RuboCop version 0.42.0.
+# on 2017-05-14 12:32:49 -0400 using RuboCop version 0.48.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
diff --git a/.travis.yml b/.travis.yml
index 8e9e432..dfedc3f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,4 @@
 language: ruby
-rvm: 2.3.1
+dist: trusty
+rvm: 2.4.1
 cache: bundler
-script: bundle exec rubocop
diff --git a/Gemfile b/Gemfile
index 748d429..e5307fc 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,8 +1,9 @@
 source 'https://rubygems.org'
 
-ruby '2.3.1' if ENV.key?('DYNO')
+ruby '2.4.1' if ENV.key?('DYNO')
 
 gem 'aws-sdk', '~> 2'
-gem 'pry', group: %i(development test)
+gem 'pry', group: %i[development test]
 gem 'rack'
-gem 'rubocop', group: %i(development test)
+gem 'rake'
+gem 'rubocop', group: %i[development test]
diff --git a/Gemfile.lock b/Gemfile.lock
index 8157052..d97491b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,33 +2,37 @@ GEM
   remote: https://rubygems.org/
   specs:
     ast (2.3.0)
-    aws-sdk (2.5.6)
-      aws-sdk-resources (= 2.5.6)
-    aws-sdk-core (2.5.6)
+    aws-sdk (2.9.17)
+      aws-sdk-resources (= 2.9.17)
+    aws-sdk-core (2.9.17)
+      aws-sigv4 (~> 1.0)
       jmespath (~> 1.0)
-    aws-sdk-resources (2.5.6)
-      aws-sdk-core (= 2.5.6)
+    aws-sdk-resources (2.9.17)
+      aws-sdk-core (= 2.9.17)
+    aws-sigv4 (1.0.0)
     coderay (1.1.1)
     jmespath (1.3.1)
     method_source (0.8.2)
-    parser (2.3.1.2)
+    parser (2.4.0.0)
       ast (~> 2.2)
     powerpack (0.1.1)
     pry (0.10.4)
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)
       slop (~> 3.4)
-    rack (2.0.1)
-    rainbow (2.1.0)
-    rubocop (0.42.0)
-      parser (>= 2.3.1.1, < 3.0)
+    rack (2.0.2)
+    rainbow (2.2.2)
+      rake
+    rake (12.0.0)
+    rubocop (0.48.1)
+      parser (>= 2.3.3.1, < 3.0)
       powerpack (~> 0.1)
       rainbow (>= 1.99.1, < 3.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (~> 1.0, >= 1.0.1)
     ruby-progressbar (1.8.1)
     slop (3.6.0)
-    unicode-display_width (1.1.0)
+    unicode-display_width (1.2.1)
 
 PLATFORMS
   ruby
@@ -37,7 +41,8 @@ DEPENDENCIES
   aws-sdk (~> 2)
   pry
   rack
+  rake
   rubocop
 
 BUNDLED WITH
-   1.12.5
+   1.14.6
diff --git a/LICENSE b/LICENSE
index ccd02ea..0dafe96 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright © 2016 Dan Buch
+Copyright © 2017 Dan Buch
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/Rakefile b/Rakefile
new file mode 100644
index 0000000..be86fd9
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,9 @@
+begin
+  require 'rubocop/rake_task'
+rescue LoadError => e
+  warn e
+end
+
+RuboCop::RakeTask.new if defined?(RuboCop)
+
+task default: %i[rubocop]
diff --git a/cpi_fetcher.rb b/cpi_fetcher.rb
index 5eb4408..cd712c0 100644
--- a/cpi_fetcher.rb
+++ b/cpi_fetcher.rb
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
 
 require 'json'
 require 'net/http'
@@ -6,7 +7,11 @@ require 'net/https'
 require 'uri'
 
 class CPIFetcher
-  DEFAULT_CPI_SERIES_URL = 'https://api.bls.gov/publicAPI/v2/timeseries/data/CUUSA210SA0'.freeze
+  DEFAULT_CPI_SERIES_URL = File.join(
+    'https://api.bls.gov',
+    'publicAPI/v2/timeseries/data/CUUSA210SA0'
+  )
+  private_constant :DEFAULT_CPI_SERIES_URL
   attr_reader :url, :bls_token
 
   def initialize