RUBY ON RAILS: how to filter index action to send json file with an user_id:value equal to localhost:user/:ID/projects NEED HELP

gistfile1.txt

class ProjectsController < ApplicationController
  before_action :set_project, only: [:show, :edit, :update, :destroy]
  skip_before_filter :verify_authenticity_token
  before_action :set_user, only: [:show, :edit,:create, :update, :destroy]
  # GET /projects
  # GET /projects.json
  def index

    @projects = Project.all
    render json: @projects

  end

  # GET /projects/1
  # GET /projects/1.json
  def show
    render json: @project
  end

  # GET /projects/new
  def new
    @project = Project.new
  end

  # GET /projects/1/edit
  def edit
  end

  # POST /projects
  # POST /projects.json
  def create
    @project = Project.new(project_params)
    @project.user_id = @user.id
      if @project.save
        render json: {status: :success, project: @project}
      else
        render json: {status: :failed, project: @project}
  end
  
  end

  # PATCH/PUT /projects/1
  # PATCH/PUT /projects/1.json
  def update
      if @project.update(project_params)
        render json: {status: :success, project: @project}
      else
        render json: {status: :failed, project: @project}
      end
  end

  # DELETE /projects/1
  # DELETE /projects/1.json
  def destroy
    @project.destroy
    respond_to do |format|
      format.html { redirect_to projects_url, notice: 'Project was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_project
      @project = Project.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def project_params
      params.require(:project).permit(:name, :descriptions, :startDate, :dueDate)
    end
    def set_user
      @user = User.find(params[:user_id])
    end 
end

gistfile2.txt

class User < ActiveRecord::Base
has_secure_password
  validates :name,
            presence: true
  validates :phonenumber,
            presence: true
  validates :email,
            presence: true,
            uniqueness: true,
            format: {
              with: /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
            }
  def to_s
    "#{name} #{phonenumber}"
  end
  has_many :projects, dependent: :destroy
  has_many :tasks, dependent: :destroy
  has_many :comments, dependent: :destroy
  
  has_many :friendships, dependent: :destroy
  has_many :friends, :through => :friendships
  has_many :inverse_friendships, :class_name => "Friendship", :foreign_key => "friend_id"
  has_many :inverse_friends, :through => :inverse_friendships, :source => :user
end

gistfile3.txt

class Project < ActiveRecord::Base
	has_many :task, dependent: :destroy
	belongs_to :user
end

gistfile4.txt

  resources :users do
    resources :friendships
    resources :projects do
      resources :tasks do
        resources :subtasks do
          resources :comments
        end
      end
    end
  end