Fix Gemfile.lock being detected as Ruby on Rails

[oleg-vinted]

This fixes a minor annoyance with Gemfile files:

• Gemfile.lock files are neither Ruby on Rails, nor Ruby files. Because there's no dedicated syntax for lock files, we're better off using plain text syntax.
• Gemfile will now be set to plain Ruby by this configuration:

  ApplySyntax/ApplySyntax.sublime-settings

  Lines 90 to 93 in faf045c

  	"syntax": "Ruby/Ruby",
  	"extensions": ["thor", "rake", "simplecov", "jbuilder", "rb", "podspec", "rabl"],
  	"rules": [
  	{"file_path": ".*/Gemfile$"},

[facelessuser]

Yeah, I don't recall where the change removed originated. It is possible things evolved and never got cleaned up. I don't use Ruby, so I'll defer to your opinion on this matter 🙂.

@gir-bot lgtm