Update README.md

Author: Peter Schiffer

README.md

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 # Linux Containers Course
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+[![Build Status](https://travis-ci.org/pschiffe/docker101.svg)](https://travis-ci.org/pschiffe/docker101)
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 Slides are available here - [josefkarasek.github.io/docker101](https://josefkarasek.github.io/docker101/) (source files can be found in the gh-pages branch)
 
 Feedback form for the second session - [schiffer.typeform.com/to/IjtF0j](https://schiffer.typeform.com/to/IjtF0j)