Create Task db

[justinjandoc]

Please do work for this task in a branch named issue-18

Within the "data_model" directory, please create a file named "task_db.dart"

• [ ] Each "task" entry should have the following elements

• id (string?)

• name (string)

• description (string

• users[] (list of user id's)

• openDate (datetime)

• dueDate (datetime)

• completionDate (datetime)

• location (string?)

• notes[] (list of note id's, default=[])

• completed (boolean)

• [ ] Create at least three instances

• [ ] Create needed methods (getTask, getUsers, setComplete, etc)