Rasa NLU in Depth - Part 2: Entity Recognition

Hey, I really suggest we should add this conversation topic in the blog post as well. Since I believe it is a very common problem, and it can be solved in different ways. It would be a good thing to conclude them. (though it is involved stories and intent design as well)

I have some ideas in my mind, let me know if you think it is helpful to write them done.