Rails 4 has_many through relationship how to add and display data with these relations?

class UserEducation < ActiveRecord::Base
       belongs_to :school
       belongs_to :subject
       belongs_to :user 
       belongs_to :degree_type
end

class DegreeType < ActiveRecord::Base
      has_many :user_educations
      has_many :users, through: :user_educations
      has_many :subjects, through: :user_educations
      has_many :schools, through: :user_educations

      validates :type, uniqueness: true
end

class Subject < ActiveRecord::Base
  has_many :user_educations
  has_many :users, through: :user_educations
  has_many :schools, through: :user_educations
  has_many :degree_types, through: :user_educations

  validates :name, uniqueness: true
end

class School < ActiveRecord::Base
has_many :user_educations
has_many :users, through: :user_educations
has_many :subjects, through: :user_educations
has_many :degree_types, through: :user_educations

validates :name, uniqueness: true
end

class User < ActiveRecord::Base
       has_many :user_educations
       has_many :schools, through: :user_educations
      has_many :subjects, through: :user_educations
      has_many :degree_types, through: :user_educations

end

private
  def user_params
      params.require(:user).permit(:about_me, :hobbies, :country,
       :gender, :avatar, :albums, :skill_list, (*What to add here for user education???*)
  end

  def set_user
    @user = User.find_by_profile_name(params[:id])
  end

 create_table "subjects", force: true do |t|
    t.string   "name"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "user_educations", force: true do |t|
    t.integer  "user_id"
    t.integer  "school_id"
    t.integer  "subject_id"
    t.integer  "degree_type_id"
    t.integer  "completion_year"
    t.datetime "created_at"
    t.datetime "updated_at"
  end
  add_index "user_educations", ["degree_type_id"], name: "index_user_educations_on_degree_type_id", using: :btree
  add_index "user_educations", ["school_id"], name: "index_user_educations_on_school_id", using: :btree
  add_index "user_educations", ["subject_id"], name: "index_user_educations_on_subject_id", using: :btree
  add_index "user_educations", ["user_id"], name: "index_user_educations_on_user_id", using: :btree

create_table "degree_types", force: true do |t|
    t.string   "type"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

create_table "schools", force: true do |t|
    t.string   "name"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

def user_params
  params.require(:user).permit(:about_me, :hobbies, :country,
       :gender, :avatar, :albums, :skill_list,
                               :school_ids => [], 
                               :subject_ids => [], 
                               :degree_type_ids => [])
end