IndianRailPnrStatus Spice Instant Answer

**What does your Instant Answer do?**
It provides the PNR status for Indian Railways

**What problem does your Instant Answer solve (Why is it better than organic links)?**
There aren't any sites currently which provide instant result. Getting PNR status by just searching on a search engine would really be helpful. 

**What is the data source for your Instant Answer? (Provide a link if possible)**
The official API provided by Indian Railways.
http://api.erail.in/

**Why did you choose this data source?**
Because it is official and it is the central source for all other PNR enquiry sites.

**Are there any other alternative (better) data sources?**
No. There are a few but there are some issues with them. Some of them are paid and some of them provide limited usage.

**What are some example queries that trigger this Instant Answer?**
pnr 4101917424
pnr 0123456789
The IA is triggered only if the query is a 10 digit number.

**Which communities will this Instant Answer be especially useful for? (gamers, book lovers, etc)**
Travellers, Passengers, Indian citizens, Tourists, General Public

**Is this Instant Answer connected to a DuckDuckHack Instant Answer idea?**
Yes.
https://duck.co/ideas/idea/4594/pnr-status-for-indian-railways

**Which existing Instant Answers will this one supercede/overlap with?**
None.

**Are you having any problems? Do you need our help with anything?**
Yes. I am having trouble with the test. One of the tests is failing. I couldn't figure out why. 
I have a query regarding the UI and about displaying other data in result.

**What does the Instant Answer look like? (Provide a screenshot for new or updated Instant Answers)**

Valid PNR:
![pnr_status_success](https://cloud.githubusercontent.com/assets/6749387/5324648/4f140f68-7d03-11e4-9090-efda30eaa59a.png)

Invalid or expired PNR:
![pnr_status_fail](https://cloud.githubusercontent.com/assets/6749387/5324665/886984a0-7d03-11e4-84ba-f46fd9d4fba3.png)


**Checklist:**

Please place an 'X' where appropriate.

[X] Added metadata and attribution information
[X] Wrote test file and added to t/ directory
[] Verified that instant answer adheres to design guidelines (https://duck.co/duckduckhack/design_styleguide)
[] Verified that instant answer adheres to code styleguide (https://duck.co/duckduckhack/code_styleguide)
[] Tested cross-browser compatibility

    Please let us know which browsers/devices you've tested on:
    - Linux
        [X] Firefox
   

A simple regex should suffix for checking our remainder only contains numbers:

```perl
my $remainder = $_;
return unless $remainder =~ m/^\d+$/; #if we know its a certain number of digits long, we can specify that too:  /^\d{9}$/;
```