Initialize README with how-to-use

[jeffreyliu]

Create documentation about the functions and how to use the templates

Should cover:

1. how to import package
2. required functions and structure for a scraper
3. the scope and interface of the scraper (what it should get, where should it write to)
4. the functions available in the template

[titaniumbones]

@jeffreyliu am I right that this templates gathers URL info but does not actually capture the body of the http response? And if I'm right, will the body be captured by sentry, or by some other entity? And finally, whether my guess is right or wrong, could this readme also include the answers to these questions (so it's very clear to new contributors)?