Merge pull request #457 from travis-ci/ha-doc-env-var-escaping

Add note for escaping bash special characters

app/templates/settings.hbs

@@ -15,6 +15,8 @@
   <section class="settings-section">
     <h2 class="small-title">Environment Variables</h2>
 
+    <p>Notice that the values are not escaped when your builds are executed. Special characters (for bash) should be escaped accordingly.</p>
+
     <ul class="settings-list--envvars">
       {{#each envVars as |envVar|}}
         <li>{{env-var envVar=envVar}}</li>