Added main gitbook manifesto files
Added main gitbook manifesto files

Note that gitbook version is fixed to 2.5.2 because more recent versions currently doesn't support
summary file in a subdirectory.
See more details on GitbookIO/gitbook#1029

baldwmic/redux-saga,granmoe/redux-saga,baldwmic/redux-saga,ipluser/redux-saga,yelouafi/redux-saga,eiriklv/redux-saga,granmoe/redux-saga,ipluser/redux-saga,HansDP/redux-saga,eiriklv/redux-saga,yelouafi/redux-saga,redux-saga/redux-saga,redux-saga/redux-saga,HansDP/redux-saga