Implement pre-hook for "git add" or "git commit

[rohandaxini]

Implementation details:

1. Add kinit to Gemfile
2. Rename config/kinit_config.yml to config/kinit.yml
3. Provide a way to add initializer for kinit configs if yml can't do that
4. Provide a way to add pre-hook commit configs in yml or initializer
5. kinit takes care of those hooks and executes those hook commands on project

Example: config/kinit.yml

best_practices:
    - bullet
    - rails_best_practices

detector:
    - reek

linter:
    - rubocop

coverage:
    - simplecov

test:
    - rspec

suggestion:
    - code_climate

prehook:
    git_add:  # or git_commit
        - rubocop
        - reek
        - simplecov