This PR updates the pygrametl website to more clearly describe the purpose of pygrametl and how it is intended to be used. Specifically the PR adds a figure that shows the components of an ETL program that is implemented using pygrametl and extends the text with more detail about how pygrametl is intended to be used. If the figure and extended text is merged, copy it to the repositories README in the master branch to keep the README and website consistent.
This PR updates the pygrametl website to more clearly describe the purpose of pygrametl and how it is intended to be used. Specifically the PR adds a figure that shows the components of an ETL program that is implemented using pygrametl and extends the text with more detail about how pygrametl is intended to be used. If the figure and extended text is merged, copy it to the repositories README in the master branch to keep the README and website consistent.