Fat_ecto - dynamically build queries

fat_ecto provides methods for dynamically building queries according to the parameters it receives.
Currently it supports the following query functions :

• where
• select
• joins
• order_by
• include

Example

    query_opts = %{
    "$select" => %{
      "$fields" => ["name", "location", "rating"],
      "fat_rooms" => ["beds", "capacity"]
    },
    "$order" => %{"id" => "$desc"},
    "$where" => %{"rating" => 4},
    "$group" => "nurses",
    "$include" => %{
      "fat_doctors" => %{
        "$include" => ["fat_patients"],
        "$where" => %{"name" => "ham"},
        "$order" => %{"id" => "$desc"},
        "$join" => "$right"
      }
    },
    "$right_join" => %{
      "fat_rooms" => %{
        "$on_field" => "id",
        "$on_join_table_field" => "hospital_id",
        "$select" => ["beds", "capacity", "level"],
        "$where" => %{"incharge" => "John"}
      }
    }

and the output will be

    iex > FatEcto.FatQuery.build(FatEcto.FatHospital, query_opts)
    #Ecto.Query<from f0 in FatEcto.FatHospital, right_join: f1 in "fat_rooms",
    on: f0.id == f1.hospital_id, right_join: f2 in assoc(f0, :fat_doctors),
    where: f0.rating == ^4 and ^true, where: f1.incharge == ^"John" and ^true,
    group_by: [f0.nurses], order_by: [desc: f0.id],
    select: merge(map(f0, [:name, :location, :rating, :id, {:fat_rooms, [:beds, :capacity]}]), %{^:fat_rooms => map(f1, [:beds, :capacity, :level])}),
    preload: [fat_doctors: #Ecto.Query<from f0 in FatEcto.FatDoctor, left_join: f1 in assoc(f0, :fat_patients), where: f0.name == ^"ham" and ^true, order_by: [desc: f0.id], limit: ^10, offset: ^0, preload: [:fat_patients]>]>