Always create AxiomSelections in migration
Always create AxiomSelections in migration

If a ProofAttemptConfiguration had no selected axioms, no AxiomSelection
was created. This violated a not null constraint on axiom_selection_id.

ontohub/ontohub,ontohub/ontohub,ontohub/ontohub,ontohub/ontohub,ontohub/ontohub,ontohub/ontohub