added contributing guidelines to the project

[santoshhiremani]

Description

Please include a summary of the change and which issue is fixed. List any dependencies that are required for this change.
If there are any UI change, please include the screenshots also.

Fixes #(issue)

Type of change

Just put an x in the [] which are valid.

• Bug fix (non-breaking change which fixes an issue)
• [x ] New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

• ./gradlew assembleDebug assembleRelease
• ./gradlew checkstyle

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

[santoshhiremani]

Project sounds very interesting and I'm looking forward to contribute more, here is my first contribution on contributor guidelines. please review my pull request. Thank you.

[Swati4star]

@santoshhiremani Welcome to project travel mate! and congrats on your first commit!

You can join slack also here for better communication!