Merge pull request #21281 from ronakjangir47/added_docs

Added docs for TimeWithZone [ci skip]

activesupport/lib/active_support/time_with_zone.rb

@@ -246,6 +246,7 @@ def future?
       utc.future?
     end
 
+    # Returns +true+ if +other+ is equal to current object.
     def eql?(other)
       other.eql?(utc)
     end
@@ -329,6 +330,11 @@ def #{method_name}    # def month
       EOV
     end
 
+    # Returns Array of parts of Time in sequence of
+    # [seconds, minutes, hours, day, month, year, weekday, yearday, dst?, zone].
+    #
+    #   now = Time.zone.now     # => Tue, 18 Aug 2015 02:29:27 UTC +00:00
+    #   now.to_a                # => [27, 29, 2, 18, 8, 2015, 2, 230, false, "UTC"]
     def to_a
       [time.sec, time.min, time.hour, time.day, time.mon, time.year, time.wday, time.yday, dst?, zone]
     end
@@ -358,11 +364,14 @@ def to_r
       utc.to_r
     end
 
-    # Return an instance of Time in the system timezone.
+    # Returns an instance of Time in the system timezone.
     def to_time
       utc.to_time
     end
 
+    # Returns an instance of DateTime in the UTC timezone.
+    #
+    #   Time.zone.now.to_datetime   # => Tue, 18 Aug 2015 02:32:20 +0000
     def to_datetime
       utc.to_datetime.new_offset(Rational(utc_offset, 86_400))
     end