Bit of Cleanup and few enhancements

- database.yml removed from git tracking.
- Specs added for vacancies controller index action.
- Vacancies can be sorted by ngo name feature added -- Enhancement #4 
- Vacancies list can be filtered and sorted -- Enhancement #5 
- Fixed - 'Post Vacancy' is getting an error when user not signed in -- Bug #6 
- Hover/Click on map marker will show more info -- Enhancement #7 
- Volunteers list can be filtered and sorted -- Enhancement #8 
- Make a proposal button and form page added - Enhancement #9 
- Terms and conditions validated during registration - Enhancement #10