Motivation

Extraordinary schema migration experience

``ts
abstract addTable: (action: bus.ducks.addTable.Action) => Promise;
abstract dropTable: (action: string) => Promise;
abstract addColumn: (action: bus.ducks.addColumn.Action) => Promise;
abstract oneToOne: (action: bus.ducks.oneToOne.Action, schema: bus.Schema) => Promise;
abstract oneToMany: (action: bus.ducks.oneToMany.Action, schema: bus.Schema) => Promise;
abstract manyToMany: (action: bus.ducks.manyToMany.Action, schema: bus.Schema) => Promise;
abstract commit: (action: bus.ducks.commit.Action) => Promise;
abstract initialize: () => Promise;
abstract getCommits: () => Promise<{ name: string; created_at: Date }[]>;
abstract beginTransaction: () => Promise;
abstract commitTransaction: () => Promise;
abstract rollbackTransaction: () => Promise;
``