Import

[jnunemaker]

I've been thinking for a while it would be nice to have a way to swap from one adapter to another. This PR makes that easy. It is not super efficient about network calls, but that can be improved later. I wanted to start with easy and correct. Plus, this is something that should happen very rarely, so if it does a few extra network calls, it probably isn't a big deal.

Example

redis_adapter = Flipper::Adapters::Redis.new
active_record_adapter = Flipper::Adapters::ActiveRecord.new

source = Flipper.new(redis_adapter)
destination = Flipper.new(active_record_adapter)

# wipes destination clean and copies features/gate values from source to it
destination.import(source)
# at this point destination == source