Looking for ideas on how to track bike wheel rotations or distance traveled I want to build a hack where when my stationary bike hits 0.1 miles, it sends an information to a webserver which would trigger a web API call.

I understand how the webserver and API call would work. I wanted some ideas on how the said hardware(mcirocontroller or other) would function on the bike itself.
Two main technologies picking bicycle speed are magnetic sensors and pickups counting wheel revolutions and ANT+/Bluetooth sensors with accelerometers  counting wheel revolutions. 

Magnetic sensor into a micro controller would be trivial and is not really a bicycle question. ANT+ sensors follow a standardized API so you could look for a micro that support ANT+ and look at the ANT+ API for bicycle sensors. 

Not sure how the accelerometers go on stationary bikes as they auto calibrate distance/revolutions, and a stationary bike has 0 distance.

I will ignore GPS...