Ensure all generated directories exist

Apply fixes from StyleCI

Use fixture name consistently

Strengthen factory generator tests

Merge pull request laravel-shift#57 from laravel-shift/model-properties

Add PHPDoc for properties of Model class

Merge pull request laravel-shift#48 from nathane/feature/change-id-co…

…lumn-datatype-to-bigincrements

Fix the migration datatype of an `id` column

Merge pull request laravel-shift#44 from laravel-shift/extensible

Register Blueprint as singleton for extensibility

Merge pull request laravel-shift#41 from laravel-shift/softdeletes-bug

Fix multiple SoftDeletes trait

Add logo and basic usage documentation to README

Ensure directories exist