linter-markdown-external#51 MWE

AtomLinter/linter-markdown#51

Steps to reproduce:

1. Make sure atom has markdown-linter package: apm install markdown-linter

2. Run the following:

git clone git@github.com:kachkaev/linter-markdown-51.git
cd linter-markdown-51
npm install

3. Add the project to Atom

4. Open README.md and see an error on line 4 (no-literal-urls)

5. Replace "external (not working)" with "external" in .remarkrc

6. Return to README.md and edit something

7.