issue_145: navigation for main app
issue_145: gem to add foundation 5
issue_145: use haml-rails gem to force haml as default template engine
issue_145: foundation 5 files generated from rails_layout. Keep off-canvas layout but adapt to generated code
issue_145: fix menu bar at the top not cover the whole icon and navigation text
issue_145: fix side menu not covering whole page
issue_145: cleanup unused partials, set nav header depending on controller
issue_145: typo lead to deleting group instead of user
issue_145: flash back messages upon CUD
cooking: issue 146
financial: issue 147
Merge branches 'cooking', 'financial' and 'issue_145' into production