BUGFIX: in 0.9 `do` takes a proc not a closure

The `do` syntax changed in 0.9, causing the code to fail with ``last argument in `do` call has non-procedure type: ||``

The code now runs (but may not be idiomatic).
Update chapter-01.md

Using for num in range( 0, 10) instead of 10.times
Merge pull request #39 from bcj/patch-1

BUGFIX: in 0.9 `do` takes a proc not a closure