Create entity DSL that allows to eliminate big part of boilerplate.

[romanowski]

Doc from DSL pasted below:

 /**
   * This is basic class to create your Entity. Entity here means database table, row and dedicated basic repository
   * together with helper classes such as unique Id type.
   * Normally, you need to generate multiple classes/objects, remember to specify correct types etc.
   * Generally a lot of boilerplate.
   * Using Entity Dsl all you need is:
   * 1. Create object that extends from `EntityDsl` with proper name (e.g. User, Invoice)
   * 2. Create inside case class `Row` representing raw row of data with one filed called `id` of type `Option[Id]`
   * 3. Create inside class Table extending `BaseTable` that represents your table (with Tag and table name).
   *    Inside Unicorn generate definition for `id` that needs to be added to `*` projection as `id.?`
   * 4. Last thing is to implement value `Repository` with new instance of `DslRepository`.
   *
   * Minimal entity looks like this:
   *
   * ```
   * object User extends EntityDsl(myProfile){
   *   case class Row(id: Option[Id], name: String)
   *   class Table(tag: Tag) extends BaseTable(tag, "Table_Name"){
   *     def name = column[String]("FIRST_NAME")
   *     override def * = (id.?, name) <> (Row.tupled, Row.unapply)
   *   }
   *   override val Repository = new DslRepository(TableQuery[Table])
   * }
   * ```
   * There still some boilerplate (e.g. `new DslRepository(TableQuery[Table])`, `<> (Row.tupled, Row.unapply)`)
   * and we plan to elimitate also those in future.
   *
   * This approach changes slightly the way how you work with your entity. Instead of using e.g. `UserRow` or
   * `UsersRepository` now `User.Row` and `User.Repository` should be used.
   * Another benefit of this approach is that now you can abstract some pieces of code around entity such as schema
   * creation.
   *
   * @param identifiers identifiers instance use together with you Unicorn instance.
   */

[romanowski]

It took me over 2 years to finally create full version. My Bad.

[pdolega]

:+1: good stuff