User send friend request

**Brief description:**

- Send from request from usera to userb. 
- You can use same method to accept friend request.

**Endpoint：**

- `https://www.mywebsite.com/api/v1.0/user_add_friend `
  
**Method:**

- POST / GET

**Parameter:**

|Parameter name|Required|Type|Explain|
|:----    |:---|:----- |-----   |
|api_key_token| Yes  |string |Your API key |
|user_a |Yes |integer | UserA ID    |
|user_b |Yes  |integer | UserB ID    |

**Example Response **

``` 
{
    "merchant": "Open Source Social Network",
    "url": "http:\/\/www.mywebsite.com\/",
    "time_token": 1569249655,
    "payload": {
        "is_friend": false,
        "request_exists": true
    },
    "code": "100",
    "message": "Request successfully executed"
}
```

**Return payload parameter description **

|Parameter name|Type|Explain|
|:-----  |:-----|-----                           |
|is_friend |boolean   | true if users are friend with each other|
|request_exists   |boolean     | true if friend request exists |

**Remark** 
- If the request succeed you should get the code 100 besides the payload.
- If you have any question you may create start a new topic on community.