Set up checkstyle

[mcupak]

Set up Checkstyle for the backend code using Maven Checkstyle Plugin.

[rishabhsethi]

I have created a pull request for this issue:
#71
Please check it.
Thanks

[mcupak]

@rishabhsethi Thanks!

A few notes though:

• Why is it set up for two of the modules only? It should work for bob-data and bob-service as well, and should be configured in the parent POM.
• Note that the parent POM fixes versions of all the components, please specify the version of the checkstyle plugin there as well.
• I think the default set of rules is too strict - can you configure it not to report stuff like 80-character line width and magic numbers in hashCode methods?

[rishabhsethi]

Thanks for the review.
I will sort this out soon.
Can you please clarify what should I check in the customized checkstyle?

[mcupak]

The two things I mentioned (plus whatever you consider appropriate, if there is anything else). I.e. line width and usage of magic numbers.

[rishabhsethi]

I have made the suggested changes. Although I am still not sure what more can be ignored from the checkstyle rules (I am sure many useless checks are still there). Will make changes as I become more familiar with the code base.

[mcupak]

I played around with the style a bit and I'd suggest going with Google's code style, which I'll update a bit once you submit a PR.

The checkstyle config is here: https://github.com/checkstyle/checkstyle/blob/master/src/main/resources/google_checks.xml

The thing I don't like in your PR is that it uses a different config file for each module - that's redundant and prone to introduce inconsistencies. Please use a single configuration file. Here's a guide describing how to use checkstyle in a multi-module Maven project: https://maven.apache.org/plugins/maven-checkstyle-plugin/examples/multi-module-config.html

Can you update the PR?

Thanks!