Add support for jobs & queueables, migrations

- Create migration directives & migrators
- Modify Cache classes to support array manipulation
- Create Redis unit and RedisCache implementation
- Create Queueable base class and Queue class that uses Cache backend

src/util/support/Pipe.ts

@@ -158,6 +158,8 @@ export type AsyncPipeResolver<T> = () => Awaitable<T>
  */
 export type AsyncPipeOperator<T, T2> = (subject: T) => Awaitable<T2>
 
+export type PromisePipeOperator<T, T2> = (subject: T, resolve: (val: T2) => unknown, reject: (err: Error) => unknown) => Awaitable<unknown>
+
 /**
  * A closure that maps a given pipe item to an item of the same type.
  */
@@ -193,6 +195,23 @@ export class AsyncPipe<T> {
         return new AsyncPipe<T2>(async () => op(await this.subject()))
     }
 
+    /**
+     * Apply a transformative operator to the pipe, wrapping it
+     * in a Promise and passing the resolve/reject callbacks to the
+     * closure.
+     * @param op
+     */
+    promise<T2>(op: PromisePipeOperator<T, T2>): AsyncPipe<T2> {
+        return new AsyncPipe<T2>(() => {
+            return new Promise<T2>((res, rej) => {
+                (async () => this.subject())()
+                    .then(subject => {
+                        op(subject, res, rej)
+                    })
+            })
+        })
+    }
+
     /**
      * Apply an operator to the pipe, but return the reference
      * to the current pipe. The operator is resolved when the