Create an aggregation which represent the number of tweet for each minute

You will have to:

• read a json file which contains 500 tweets
• extract date from each tweet
• Count the number of tweets for each minute
• Write result in a separate file

sample/tweets.json

looks like

[
  {
    "id_str": "687345183503994880",
    "text": "We're #hiring! Read about our latest #job opening here: Key Holder - https://t.co/DJUvBlpK7b #ElPaso, TX #CareerArc",
    /* 
      ...
    */
    "timestamp_ms": "1452710836660",
    /* 
      ...
    */
    "created_at": "2016-01-13T18:47:16.660Z"
  },
  /* 
    ...
  */

Use one of the two fields timestamp_ms or created_at to aggregate tweets

Note: tweet with "created_at": "2016-01-13T18:47:16.660Z" Should be aggregate at the previous minute (18:47) Never to the next minute, even if seconds are closer to the next one

18h 46m 16s => 18h46
18h 46m 59s => 18h46
18h 47m 20s => 18h47

Write your result in result.json

Output file should look like this

[{
  "time": 1453199640000
  "count": 12
},{
  "time": 1453199700000
  "count": 12
}
/* ... */
]

• time is the timestamp of the previous minute.
• count is the number of tweet for this minute.

Fork the project, code your solution, then create a Pull Request to provide your solution.

Feel free to code with your favorite language.