Remove no-longer-necessary dependency

erubis used to be required by haml (a dependency of rdf-rdfa) and now we updated rdf-rdfa to allow newer versions of haml that do not require erubis.

Fixes #436

Gemfile

@@ -4,8 +4,6 @@ gem 'bootstrap', '~> 4.1.3'
 gem 'config'
 gem 'devise'
 gem 'devise-remote-user'
-gem 'dor-services-client', '~> 0.6'
-gem 'erubis' # implicit dependency for (old) rdf-rdfa, no longer default in Rails 5.1+
 gem 'honeybadger', '~> 3.1'
 gem 'jbuilder'
 gem 'jquery-rails'
@@ -31,6 +29,7 @@ gem 'capistrano-resque-pool'
 gem 'assembly-image'
 gem 'assembly-objectfile', '~> 1.7'
 gem 'dor-services', '~> 5.29'
+gem 'dor-services-client', '~> 0.6'
 
 group :test do
   gem 'coveralls', require: false

Gemfile.lock

@@ -209,7 +209,6 @@ GEM
     equivalent-xml (0.6.0)
       nokogiri (>= 1.4.3)
     erubi (1.8.0)
-    erubis (2.7.0)
     execjs (2.7.0)
     factory_bot (4.11.1)
       activesupport (>= 3.0.0)
@@ -544,7 +543,6 @@ DEPENDENCIES
   dor-services (~> 5.29)
   dor-services-client (~> 0.6)
   equivalent-xml
-  erubis
   factory_bot_rails
   honeybadger (~> 3.1)
   jbuilder

config/application.rb

@@ -1,6 +1,5 @@
 require_relative 'boot'
 require 'rails/all'
-require_relative 'erubis_monkeypatch.rb'
 
 CERT_DIR = File.join(File.dirname(__FILE__), '.', 'certs')