add tap coverage example to project settings

Previously, there were examples for Simplecov, pytest-cov, and phpunit.
This adds an example for using the tap cli tool
(https://github.com/tapjs/node-tap)

app/views/projects/_builds_settings.html.haml

@@ -55,6 +55,9 @@
           %li
             gcovr (C/C++) -
             %code ^TOTAL.*\s+(\d+\%)$
+          %li
+            tap --coverage-report=text-summary (Node.js) -
+            %code ^Statements\s*:\s*([^%]+)
 
   .form-group
     .col-sm-offset-2.col-sm-10