Implement a token system #78

[suresh-kumara-gist]

Test this functionality in ./scripts/node-cli.sh:-

1. Create and store token string of length 6 and its hash.

> await app.c('tokens').newToken({
    name: 'something',
    permissions: ['some-permission', 'another-permission'],
    whatever: 'hello world',
    _length: 6,
    _digits_only: false
  });

it will return string of length 6 as a token as a response.

await app.c('tokens').checkToken('something', '<replace token here>');

it would return true i.e.. token is valid.

next try this:-

await app.c('tokens').checkToken('something', '<some value>');

it would return null i.e.. no record found for that token.

2. Create and store 6 digits token and its hash.

  await app.c('tokens').newToken({
    name: 'something',
    permissions: ['some-permission', 'another-permission'],
    whatever: 'hello world',
    _length: 6,
    _digits_only: true
  });

it would return 6 digits token as a response.

  await app.c('tokens').checkToken('something', '<replace token here>');

it would return true i.e.. token is valid.

next try this:-

  await app.c('tokens').checkToken('something', '522559');

it would return null i.e.. no record found for that token.

[suresh-kumara-gist]

I have to update README and add test cases for this PR.