Allowed showing line numbers

Author: ijlee2

app/components/code-snippet/template.hbs

@@ -3,5 +3,6 @@
     data-test-code-snippet
     @code={{snippet.source}}
     @language={{get-prism-language snippet.language}}
+    @showLineNumbers={{true}}
   />
 {{/let}}

ember-cli-build.js

@@ -12,6 +12,9 @@ module.exports = function(defaults) {
         'handlebars', 'markup-templating', // handlebars
         'bash' // shell
       ],
+      plugins: [
+        'line-numbers'
+      ]
     },
 
     prember: {