add simplecov to gemfile
verify that a user cannot edit another user's tags
add foundation to gemfile
styling for top bar navigation
background color, navigation, add autofocus
top bar dividers, button color
styling for recipes index page
add javascript for clear form button
alert and notice styling
update notice and alert messages for consistency
add padding between top bar and page content
recipes index: button placement
recipe form styling
styling: top of recipe show page
styling: recipe ingredients and directions
Fix model and display issues for recipe time.

- Recipe#calculate_time now works properly when a previously-specified time is removed.
sticky top bar navigation, adjust header font sizes
restyle search/filter box to take up less of recipes index
add tags to main section, make top bar un-sticky
styling: recipe comments, edit recipe form and index