Lock light state using the Light class interface

[Lokideos]

To manually lock the state of light, we use the data_store interface. For example:

light = Stoplight('example-locked') { true }
# => #<Stoplight::Light:..>
light.run
# => true
light.data_store.set_state(light, Stoplight::State::LOCKED_RED)
# => "locked_red"
light.run
# Stoplight::Error::RedLight: example-locked

However, it allows us to use the interface of one light to lock the state of any other light. To avoid this situation, I'd like to add the Light#set_state method, which will be called like this:

light = Stoplight('example-locked') { true }
light.set_state(Stoplight::State::LOCKED_RED)

This implementation will clearly show for what light we lock the state.

[bolshakov]

Maybe instead of emphasizing setting state, we can emphasize locking the circuit breaker:

light = Stoplight('example-locked') { true }
light.lock(Stoplight::Color::RED) 

Users don't have to know about the Stoplight::State::LOCKED_RED which is internal details aimed to distinguish red statute from locked red. What do you think?

[Lokideos]

@bolshakov yes, that's a great idea! I also think that to unlock it, we can just use the Light#unlock method without any arguments. WDYT?

[bolshakov]

This makes sense to me