Add support for linting GraphQL with ESLint

ale_linters/graphql/eslint.vim

@@ -0,0 +1,9 @@
+" Author: Benjie Gillam <code@benjiegillam.com>
+" Description: eslint for GraphQL files
+
+call ale#linter#Define('graphql', {
+\   'name': 'eslint',
+\   'executable_callback': 'ale#handlers#eslint#GetExecutable',
+\   'command_callback': 'ale#handlers#eslint#GetCommand',
+\   'callback': 'ale#handlers#eslint#Handle',
+\})