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 &lt;null&gt;  
* Some simple tests

### What's next: 
* Hopefully importing the crops. 
* Start implementing more mutations (for crop)
* Finish guide updating, it's hanging there.