Fix README.md and package.json

[FPNL]

For reason below and https://github.com/vcapretz/bull-board/blob/master/src/index.ts#L43,
package.json should be temporarily changed, that developer can use it.

internal/modules/cjs/loader.js:638
    throw err;
    ^

Error: Cannot find module 'bullmq'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
    at Function.Module._load (internal/modules/cjs/loader.js:562:25)
    at Module.require (internal/modules/cjs/loader.js:692:17)
    at require (internal/modules/cjs/helpers.js:25:18)
    at Object.<anonymous> (/Users/xillis_wu/Documents/chungyo/pineapple-job/node_modules/bull-board/dist/index.js:8:18)
    at Module._compile (internal/modules/cjs/loader.js:778:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
    at Module.load (internal/modules/cjs/loader.js:653:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
    at Function.Module._load (internal/modules/cjs/loader.js:585:3)

[felixmosh]

Thank you for the PR,
The readme is already updated in #169.

Regarding the usage of bull-mq, we discus it here: #167, a fix will be released asap,
For the meanwhile, you can install devDeps as well