Make bootsnap MRI only for now

Gemfile

@@ -2,8 +2,7 @@ source 'https://rubygems.org'
 # if there is a super emergency and rubygems is playing up, try
 #source 'http://production.cf.rubygems.org'
 
-# does not install in linux ATM, so hack this for now
-gem 'bootsnap', require: false
+gem 'bootsnap', require: false, platform: :mri
 
 def rails_master?
   ENV["RAILS_MASTER"] == '1'

config/boot.rb

@@ -11,14 +11,20 @@
 require 'bundler/setup' if File.exists?(ENV['BUNDLE_GEMFILE'])
 
 if ENV['RAILS_ENV'] != 'production' && ENV['RAILS_ENV'] != 'profile'
-  require 'bootsnap'
+  begin
+    require 'bootsnap'
+  rescue LoadError
+    # not a strong requirement
+  end
 
-  Bootsnap.setup(
-    cache_dir:            'tmp/cache', # Path to your cache
-    load_path_cache:      true,        # Should we optimize the LOAD_PATH with a cache?
-    autoload_paths_cache: true,        # Should we optimize ActiveSupport autoloads with cache?
-    disable_trace:        false,       # Sets `RubyVM::InstructionSequence.compile_option = { trace_instruction: false }`
-    compile_cache_iseq:   true,        # Should compile Ruby code into ISeq cache?
-    compile_cache_yaml:   false        # Skip YAML cache for now, cause we were seeing issues with it
-  )
+  if defined? Bootsnap
+    Bootsnap.setup(
+      cache_dir:            'tmp/cache', # Path to your cache
+      load_path_cache:      true,        # Should we optimize the LOAD_PATH with a cache?
+      autoload_paths_cache: true,        # Should we optimize ActiveSupport autoloads with cache?
+      disable_trace:        false,       # Sets `RubyVM::InstructionSequence.compile_option = { trace_instruction: false }`
+      compile_cache_iseq:   true,        # Should compile Ruby code into ISeq cache?
+      compile_cache_yaml:   false        # Skip YAML cache for now, cause we were seeing issues with it
+    )
+  end
 end