Include email address explicitly in welcome email to avoid any confusion

services/web/app/coffee/Features/Email/EmailBuilder.coffee

@@ -13,7 +13,7 @@ templates.welcome =
 	compiledTemplate: _.template '''
 <p>Hi <%= first_name %>,</p>
 
-<p>Thanks for signing up to ShareLaTeX! If you ever get lost, you can log in again <a href="<%= siteUrl %>/login">here</a>.</p>
+<p>Thanks for signing up to ShareLaTeX! If you ever get lost, you can log in again <a href="<%= siteUrl %>/login">here</a> with the email address "<%= to %>".</p>
 
 <p>If you're new to LaTeX, take a look at our <a href="<%= siteUrl %>/learn">Help Guides</a> and <a href="<%= siteUrl %>/templates">Templates</a>.</p>