Update CONTRIBUTING.md

Language corrections (as well as spelling Linnovate right!). I would very much prefer you include a copyright assignment clause. Here you are only licensing the contribution. Some communitied do not like copyright assignment, but I personnaly, for this piece of code find it simpler.  At least for larger contributions and contributions made by companies. See http://dreamsongs.com/ihe/IHE-110.html for an example clause..
fix linnovate/meanio#3
Merge pull request #27 from OriPekelman/patch-1

Update CONTRIBUTING.md
new postinstall script
postinstall refactor
fix of postinstall script
fix linnovate/mean#782
bring git repo versioning inline with npm - 0.5.31
changing install script from meanjson to shell.exec as temp fix for order issue, need to use  instead
Merge branch 'master' of github.com:linnovate/mean-cli
bump version
enable aggregation from remote url

fix #32
0.5.34
Merge remote-tracking branch 'upstream/master'
defaultMenu problem fixed in order to be backward compatible