Create Repository assembly

[radike]

Controllers should use repositories instead of directly using DbContext.

[damolh]

prototype is accessible on slack or http://ulozto.cz/xWawRwtn/issuetracker-source-zip

[radike]

• use AutoMapper instead of implementing own mapper "SimpleMapper"
• please, make sure that the purpose of every new project is clear and the name reveals its content

[radike]

Update! ccc6623e316f7d104f83a48a0ad7ed51a24cc029 @damolh please, reference the issue in commit message like this '#31'

[radike]

Notes from our brainstorming:

• remove empty IDataRepository interface or make it useful
• rename generic types to something descriptive e.g. from T to TEntity
• add DTO assembly

[radike]

Notes from our brainstorming:

• assemblies should be in real folders = assemblies organization
• repositories should use db context per request
• move DataRepositoryBase to IssueTracker.Entities
• add repositories metods to interfaces in IssueTracker.Data.Contracts
• IIdentifiableEntity should be in IssueTracker.Entities
• DTOs are required, it is not a good design practice to replace DTOs with entities without data annotations and configurations replacing data annotations .. but this should not block our progress => minor issue

[radike]

Closing this issue because the repositories are implemented and other minor issues will be solved in the future (probably as part of the task #61).