Add method to convert an interval into a collection

[tartakynov]

I think it would be useful to have a method to convert an interval to immutable collection of dates, like SortedSet, with specified step. The main goal is to be able to utilize Scala collections API out of the box

(start to end).toSeq(step).map(date => ???)

[wookietreiber]

I have been doing something like this, too:

implicit class RichInterval(self: Interval) {
  import org.joda.time.ReadablePeriod

  def by(d: ReadablePeriod) = {
    val coll = collection.mutable.ListBuffer[DateTime]()

    var x = self.start
    while (x < self.end) {
      coll += x
      x += d
    }

    coll.toList
  }
}

[wookietreiber]

I'd be glad to provide a PR on this. Maybe we can even take a builder or so and make it:

def by[Coll](...)(implicit ...): Coll[DateTime] = ???

... like the to[Coll] method in scala collections library.

[gakuzzzz]

cool 👍