Ask HN: Hiring a Rails developer for a PHP role?

Hey everyone - I'm the CTO of an early stage startup with me as the only developer right now. My go-to language is PHP, and so far the product is built entirely on PHP/Laravel.

We're looking to hire a developer, and it will just be me and him/her programming for the next 6 months or so. It's been tough finding a solid PHP developer. However, we have found a lot of Rails devs who appear pretty solid.

So, my question to the HN community: is it advisable to hire a non-PHP developer even though there will be some learning time spent? How long would you expect it to take to "switch" languages? The reason I ask is that we're on tight timelines.

Thanks in advance!