split diff per file
introduce DiffsController
remove diff action from files controller
split diff computation into many small functions
add specs on DiffsController
add spaces around assignment operator
shorten line
clean the code, fix diff of first commit retrieval
Merge branch 'staging' into 865-introduce-diffs-controller
Merge pull request #1055 from ontohub/865-introduce-diffs-controller

865 introduce diffs controller