You can also write as follows:
Current time:
x = Time.now => 2017-02-14 11:55:17 +0530
an hour ago (an hour before):
y = x - 1.hour => 2017-02-14 10:55:17 +0530
or
y = 1.hour.ago => 2017-02-14 10:55:17 +0530 `# available in rails v4.2
in an hour / in (in an hour after):
z = x + 1.hour => 2017-02-14 12:55:17 +0530
or
z = 1.hour.since => 2017-02-14 12:55:17 +0530 # available in rails v4.2
: x ( ) (Time.now), , (Time.now)