ChefPosition (Executive, Sous, etc...)
Skills (Creativity, speed, quality)

ChefPositionSkill (chef_position_id, skill_id)

ChefPositionSkillController < ApplicationController

  def index
    @ChefPositionSkills = Skill.where(:chef_position => params[:chef_position_id]
    render json: @ChefPositionSkills, status: status
  end
end

chef_positions
* id
* name
* ...

skills
* id
* name
* ...

chef_position_skills
* id
* chef_position_id
* skill_id

class ChefPosition < ApplicationRecord
  has_many :chef_position_skills
  has_many :skills, through: :chef_position_skills
end

class Skill < ApplicationRecord
  has_many :chef_position_skills
  has_many :chef_positions, through: :chef_position_skills
end

class ChefPositionSkill < ApplicationRecord
  belongs_to :chef_position
  belongs_to :skill
end

resources :chef_positions, only: [] do
  resources :chef_position_skills, only: [:index]
end

class ChefPositionSkillsController < ApplicationController
  def index
    chef_position = ChefPosition.find(params[:chef_position_id])
    render json: chef_position.chef_position_skills
  end
end