ayjay questions

• Difference between the "@" instance variable belonging to the class object and "@@" class variable in Ruby? [duplicate]
• Would I need to undo a "rails generate scaffold" after I undo a "db:migrate"?
• How to rename "PREFIX" in Amazon s3 via aws cli?
• Updating CSS via plain JavaScript... how do I update if the property uses vendor prefixes?
• Why does `position:fixed` not work when viewed in an `iframe` using an iPhone or iOS device?
• When I ran `bundle exec rake test:prepare` it errored out, but `bundle exec rake db:test:prepare` goes through fine with warning. What's going on?

ayjay answers