esell: add main.go for learning
esell: add main.go for learning

Change-Id: I3dfa1ca4ca9054ea243d3dbc48052c665633d82c
Reviewed-on: https://go-review.googlesource.com/132261
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

golang/scratch