Ruby convention for chaining calls over multiple lines

There is actually a section on that in the Ruby style guide:

Adopt a consistent multi-line method chaining style. There are two
popular styles in the Ruby community, both of which are considered
good – leading . (Option A) and trailing . (Option B).

• (Option A) When continuing a chained method invocation on
  another line keep the . on the second line.

  # bad - need to consult first line to understand second line
  one.two.three.
    four
  
  # good - it's immediately clear what's going on the second line
  one.two.three
    .four
  

• (Option B) When continuing a chained method invocation on another line,
  include the . on the first line to indicate that the
  expression continues.

  # bad - need to read ahead to the second line to know that the chain continues
  one.two.three
    .four
  
  # good - it's immediately clear that the expression continues beyond the first line
  one.two.three.
    four
  

A discussion on the merits of both alternative styles can be found
here.