create task rest controller

tasx-23
implement task rest controller index and show actions

tasx-23
prevent NullPointerException with safe navigation operator

tasx-23
make user rest controller return empty map if null user

tasx-23
Merge branch 'feature/tasx-6-task-view-controller' into feature/tasx-23-task-rest-api
consolidate code in task service class

tasx-23
move task serializer from service to domain class

tasx-23
define date format in configuration file

tasx-23
Merge pull request #14 from osu-mist/feature/tasx-23-task-rest-api

Feature/tasx 23 task rest api