Only one order by can be handled

[TimothyGillespie]

Describe the Bug
The .order() method on the Query overwrites itself and only saves the last instance. This makes it impossible to sensible write queries which require multiple order by statements.

To Reproduce
repo.query().order("x").order("y");

Expected behavior
Should not throw away previous orders.

Screenshots / Logs
None

Environment Information:

• Java Language Level :

Additional Context
None

[TimothyGillespie]

See #21, the last few tests to see the issue

[TimothyGillespie]

This will be merged from #24 into #19 and then into the master branch. Solution exists.