tracking_get: Return page from tracking sheet as tibble
In mgunther87/ipumsPMA: Common functions for IPUMS PMA staff

Description Usage Arguments Note Author(s) Examples

Reads user's Google Drive for a specified tracking sheet (currently one of "sdp", "hhf", "mnh", or nut"), and either of sheets therein (one of "new" or "updated"). Alternatively, the user may specify the URL of a page in any tracking sheet.

tracking_get(
  unit = c("sdp", "hhf", "mnh", "nut"),
  sheet = c("new", "updated"),
  url
)

`unit`	Character: Must be "sdp", "hhf", "mnh", or "nut".
`sheet`	Optional: For units "sdp" or "hhf", user must specify "new" or "updated". Units "mnh" and "nut" have no updated vars at this time, so the sheet containing new variables will be imported automatically.
`url`	Optional: A url to the specific page on a Google Sheet. If provided, this will supersede other arguments.

Access to Google Drive depends on user permissions, which must be refreshed as frequently as access token expires. A pop-up browser window requesting permission should appear when function is first called.

Matt Gunther

## Not run: 
# Get the "new" sheet from the SDP tracking sheet
tracking_get("sdp", "new")

# Get the "updated" sheet from the SDP tracking sheet
tracking_get("sdp", "updated")

## End(Not run)