Add organisations api specs.
Add organisations api specs.

wicky-info/github,yaoxiaoyong/github,befairyliu/github,davengeo/github,joshsoftware/github,durai145/github,piotrmurach/github,firstval/github,MalachiTatum/github,cocktail-io/github,GistBox/github,peter-murach/github,anabhilash619/github,samphilipd/github