Initialise testing suite with rspec

Changes made:
- Generate rspec files with rails g method.
- Add factory girl linting and database cleaner calls to rails_helper.
- Generate guard files to automate running of rspec tests.
- Add -fd flags to .rspec for a more descriptive test output.
- Add valid factory for participant location
- Fill participant location test with some methods.
Implement Geocoder for participant locations

Follow Geocoder guide to implement two methods which will geocode an
address. Found here:

https://github.com/alexreisner/geocoder#activerecord
Add reasoning behind building the location factory

Clarifies how I came to the conclusion to this factory and its
properties.