The plugin doesn't work properly with current trunk version.
You have to create config and config/locales directory and place the en.yml file in there.
css style issue¶
You may get a problem in vendor/plugin/redmine_my_effort/app/views/issues/show.rhtml:line 19:
<div class="<%= css_issue_classes %> details">
which can be fixed with:
<div class="<%= @issue.css_classes %> details">