Document permissions required for database users

[jewzaam]

For each backend, need to document permissions required to allow all operations to work.

[jewzaam]

Per Mongodb Doc :-

http://docs.mongodb.org/manual/reference/built-in-roles/

readWrite

     Provides all the privileges of the read role plus ability to modify 
data on all non-system collections and the system.js collection. The 
role provides the following actions on those collections:

         collStats
         convertToCapped
         createCollection
         dbHash
         dbStats
         dropCollection
         createIndex
         dropIndex
         emptycapped
         find
         insert
         killCursors
         remove
         renameCollectionSameDB
         update