[WIP] Ecto integration

[zoedsoupe]

Description

Provide seamlessly integration with Ecto, providing a new function to_changeset!/2 that receives a peri schema and the data to be validated, acting like a common changeset/2 function.

This function will translate all possible peri type definitions to ecto ones, using ecto schemaless changesets and custom ecto types implemented on Peri.Ecto.Type.* modules, that can be used alone on your other Ecto schemas, for example:

• Peri.Ecto.Type.Atom
• Peri.Ecto.Type.PID
• Peri.Ecto.Type.Tuple
• Peri.Ecto.Type.Either
• Peri.Ecto.Type.OneOf

Also, notice that Ecto doesn't support raw data structures validations, so to_changeset!/2 only accepts a map peri schema, will raise otherwise.

It also supports nested schemas, respecting above rules, and also nested composite types, like tuple of maps, or either maps or oneof maps and so on (wip right now).

Related Issues

This PR will close #3

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Checklist

• My code follows the style guidelines of this project.
• I have performed a self-review of my code.
• I have commented on my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.

Additional Context

Just to track the already supported types implemented on this PR:

• :any
• :atom
• :integer and all custom validations :eq, :neq, :gt, :gte, :lt, :lte, :range
• :float and all custom validations :eq, :neq, :gt, :gte, :lt, :lte, :range
• :map
• :boolean
• :string and all those custom validations like :eq, :min, :max, :regex
• :date
• :time
• :datetime
• :naive_datetime
• :duration
• :pid via custom ecto type
• {type, {:default, val}} for setting default values
• {:enum, choices} via Ecto.Enum
• {type, {:transform, mapper}} via Ecto.Changeset.update_change/3
• {:required, type} via Ecto.Changeset.validate_required/2
• {:list, type} via Ecto {:array, type}
• {:tuple, types} via custom Ecto type
• {:either, {fat, snd}} via custom Ecto type
• {:oneof, types} via custom Ecto type
• nested schemas
• nested array schemas
• nested schemas on :oneof
• nested schemas on :either
• nested schemas on :tuple
• {:cond, condition, true, false}
• {:dependent, field, condition, type}
• {:dependent, condition}
• {:dependent, {mod, fun}}
• {:custom, callback}
• {:custom, {mod, fun}}
• {:custom, {mod, fun, args}}