Hh refactor

Hey Michael,

Great job on the systems check.  It looks really good.  I made edits in this pull request (click on "Files changed" or "commits" to view), but here's a summary:

**Use exec_params to avoid SQL injection.** For the `/recipes/:id` page, users could pass in nasty stuff like "5; DROP TABLE recipes;" as `params[:id]` and blow up your app unless you use `exec_params` to thwart their malicious intent.

**Use methods to query the database.** It's generally good practice to extract as much code as you can out of your `get` and `post` blocks into methods.  Ideally, your `get` and `post` blocks merely create instance variables and render views, so they're like 2-3 lines.

**Indentation.** Make sure to follow conventions on indentation!  The sooner you get used to indenting things properly the better.  It'll become super important once we get to bigger apps and employers see sloppy indentation as a mark of inexperience/lack of professionalism.

**Start calling your views `index.erb` and `show.erb` just to get used to the Rails conventions.** You don't need to do this but it's probably a good idea to start doing it going forward.

Nice job using multiple smaller commits in git.  Most people aren't doing that yet.

Let me know if you have any questions :)

Helen