Added "Prolog Problems"
Added "S-99: Ninety-Nine Scala Problems"
[es] added 3 books of Eugenia Bahit
Add Git Workflows
Merge pull request #625 from Mouseion/patch-gitbook

Add Git Workflows
Merge pull request #623 from alexanderfefelov/master

Added a few books
Merge pull request #624 from esparta/master

[es] added 3 books of Eugenia Bahit
Merge remote-tracking branch 'upstream/master'
[es] Adding node.js to the list.
Merge pull request #626 from matysanchez/master

[es] Adding node.js to the list.
Add bunch of interactive tutorials
Add githug tutorial (in the shell)
Add Learn Linux The Hard Way guide
Merge pull request #627 from JIghtuse/master

Add more interactive tutorials and guide on Linux
[es] minimal fix & secondary link (a PDF) to 'Python para principantes'
Added "tetrix in Scala" (EN, JA)
Added "Программирование на Эрланге"
Added "Developing Web Applications with Haskell and Yesod" (RU)
Alphabetized Haskell section
Added "Exploring Generic Haskell"