Add vim-test alternatives for Rails request specs

This also supports feature and system tests, by defining projections.

tpope/vim-rails#368 (comment)

vim/ftplugin/ruby.vim

@@ -0,0 +1,36 @@
+let g:rails_projections = {
+      \  "app/controllers/*_controller.rb": {
+      \      "test": [
+      \        "spec/requests/{}_spec.rb",
+      \        "spec/features/{}_spec.rb",
+      \        "spec/system/{}_spec.rb",
+      \        "spec/controllers/{}_controller_spec.rb",
+      \        "test/controllers/{}_controller_test.rb"
+      \      ],
+      \      "alternate": [
+      \        "spec/requests/{}_spec.rb",
+      \        "spec/features/{}_spec.rb",
+      \        "spec/system/{}_spec.rb",
+      \        "spec/controllers/{}_controller_spec.rb",
+      \        "test/controllers/{}_controller_test.rb"
+      \      ],
+      \   },
+      \   "spec/requests/*_spec.rb": {
+      \      "command": "request",
+      \      "alternate": "app/controllers/{}_controller.rb",
+      \      "template": "require 'rails_helper'\n\n" .
+      \        "RSpec.describe '{}' do\nend",
+      \   },
+      \   "spec/features/*_spec.rb": {
+      \      "command": "feature",
+      \      "alternate": "app/controllers/{}_controller.rb",
+      \      "template": "require 'rails_helper'\n\n" .
+      \        "RSpec.feature '{}' do\nend",
+      \   },
+      \   "spec/system/*_spec.rb": {
+      \      "command": "system",
+      \      "alternate": "app/controllers/{}_controller.rb",
+      \      "template": "require 'rails_helper'\n\n" .
+      \        "RSpec.describe '{}' do\nend",
+      \   },
+      \ }