Instructions for dumps and elasticsearch index; add pry-debugger and pry-stack_explorer for better development.

@baileyspace After loading the data dump locally, to actually be able to see the data in the app, I had to reindex the elasticsearch index. Because this was not in the README, I felt that it was important to add it for posterity. 

I've also added pry-debugger and pry-stack_explorer to easily step through code. :rocket: