added slug field to categories table , refs #31
added category slug functionality, refs #31
db migration , added slug field to destinations table, refs #31
destination is sluggable now also, refs #31
added slug field to packages table, refs #31
package is now sluggable, refs #31
added task to update category/destination/package slugs , resolves #31
Merge branch 'feature/feature-#31' into develop