Add Rake for importing data

### What's New:
* Added a Crop Data Source. Should maybe be discussed a bit more.
* Import file line by line instead of all in one go.
* Don't crash on <null>
* Some simple tests

### What's next: 
* Hopefully importing the crops. 
* Start implementing more mutations (for crop)
* Finish guide updating, it's hanging there. 
Prefer single-quoted strings when you don't need string interpolation or special symbols.