Merge pull request #24 from SurojitMandal/master

Merge into OctoFalcon/astrid
Merge pull request #25 from SurojitMandal/master

Merge into OctoFalcon/astrid
Merge pull request #26 from SurojitMandal/master

Inventory is added
Added top category and get category by id
Merge pull request #8 from OctoFalcon/master

Merge from OctoFalcon/astrid to SurojitMandal/astrid