Merge pull request #2 from reinaris/master

Added moneybird ID to spree tax category
Don't sync payments twice
Sync in batches
Mark invoices as "completed"
Order must be completed before sync
Only create invoices of shipped orders
Use the country.name instead of the iso code
Merge pull request #3 from reinaris/patch-1

Use the country.name instead of the iso code
Fixed spec
Fixed double contact sync bug
Use user id instead of moneybird id
Working on guest id's
The magic user id

Money bird assigns automatically customer-ids. Resulting in conflicting
ids
send invoice callback for @reinaris
use tax rate instead of tax category
Merge pull request #7 from reinaris/use_tax_rates

Use Tax Rate id instead of Tax Category
Updatable attributes
Merge pull request #8 from reinaris/updatable-attributes

Updateble attributes
Revert "Updateble attributes"
Merge pull request #9 from Willianvdv/revert-8-updatable-attributes

Revert "Updateble attributes"