RUBY

ruby string to date

str = "Tue, 10 Aug 2010 01:20:19 +0400"
puts Date.parse str
2010-08-10
puts Date.parse(Time.parse(str).utc.to_s)
2010-08-09

Or simply
Time.zone.parse(str) # using Time with zone is a good rule of thumb

convert string to date ruby

date = Date.strptime(start_date, ‘%d/%m/%y’)