Bump gems and switch to erubi

Gemfile

@@ -14,7 +14,7 @@ group :app do
   gem 'thin'
   gem 'sprockets'
   gem 'sprockets-helpers'
-  gem 'erubis'
+  gem 'erubi'
   gem 'browser'
   gem 'sass'
   gem 'coffee-script'

Gemfile.lock

@@ -19,17 +19,18 @@ GEM
     coffee-script-source (1.12.2)
     concurrent-ruby (1.0.4)
     daemons (1.2.4)
+    erubi (1.5.0)
     erubis (2.7.0)
     ethon (0.10.1)
       ffi (>= 1.3.0)
-    eventmachine (1.2.1)
+    eventmachine (1.2.2)
     execjs (2.7.0)
     ffi (1.9.17)
     highline (1.7.8)
     html-pipeline (2.5.0)
       activesupport (>= 2)
       nokogiri (>= 1.4)
-    i18n (0.7.0)
+    i18n (0.8.0)
     method_source (0.8.2)
     mini_portile2 (2.1.0)
     minitest (5.10.1)
@@ -52,7 +53,7 @@ GEM
     rake (12.0.0)
     rr (1.2.0)
     sass (3.4.23)
-    sinatra (1.4.7)
+    sinatra (1.4.8)
       rack (~> 1.5)
       rack-protection (~> 1.4)
       tilt (>= 1.3, < 3)
@@ -75,7 +76,7 @@ GEM
       rack (>= 1, < 3)
     thor (0.19.4)
     thread_safe (0.3.5)
-    tilt (2.0.5)
+    tilt (2.0.6)
     tty-pager (0.5.0)
       tty-screen (~> 0.5.0)
       tty-which (~> 0.2.0)
@@ -104,7 +105,7 @@ DEPENDENCIES
   better_errors
   browser
   coffee-script
-  erubis
+  erubi
   html-pipeline
   minitest
   nokogiri

lib/app.rb

@@ -6,7 +6,7 @@ Bundler.require :app
 class App < Sinatra::Application
   Bundler.require environment
   require 'sinatra/cookies'
-  require 'tilt/erubis'
+  require 'tilt/erubi'
   require 'active_support/notifications'
 
   Rack::Mime::MIME_TYPES['.webapp'] = 'application/x-web-app-manifest+json'