ERB files grammar is not correct

[deiga]

Prerequisites

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Description

PR #181 introduced a very subtle bug, which can't be reproduced other than in a very controller environment

Steps to Reproduce

1. Disable package language-ruby-on-rails
2. Reload editor
3. Open a file with a plain .erb extension
4. Set syntax to Auto Detect

Expected behavior:
File syntax should be Ruby or Embedded Ruby or something and scope should be source.ruby.embedded or something

Actual behavior:
Syntax is Plain Text and scope is text.plain.null-grammar

Reproduces how often:

100%

Versions

Atom: 1.18.0
Electron: 1.3.15
apm: 1.18.1
macOS 10.12.5

Additional Information

It seems that removing erb from HTML (Ruby - ERB) grammar left a hole where there is no actual grammar for .erb files defined