Add package-lock.json and .gitignore

[bhaveshAn]

Actual Behaviour

Currently, package-lock.json is not committed.

Expected Behaviour

package-lock.json should be committed. See here https://stackoverflow.com/questions/44206782/do-i-commit-the-package-lock-json-file-created-by-npm-5#answer-44210813

 package-lock.json is automatically generated for any operations where npm modifies either the node_modules tree, or package.json. It describes the exact tree that was generated, such that subsequent installs are able to generate identical trees, regardless of intermediate dependency updates.

Yes I would like to work on this issue.