Adds index and show defs, and relatives unit tests

app/controllers/api/v1/tasks_controller.rb

@@ -0,0 +1,22 @@
+class Api::V1::TasksController < ApplicationController
+  before_action :set_task, only: %i[show update destroy]
+  before_action :check_login
+
+  def index
+    render json: TaskSerializer.new(Task.all).serializable_hash.to_json
+  end
+
+  def show
+    render json: TaskSerializer.new(@task).serializable_hash.to_json
+  end
+
+  private
+
+  def task_params
+    params.require(:task).permit(:name, :description, :user_id, :activity_id)
+  end
+
+  def set_task
+    @task = Task.find(params[:id])
+  end
+end

app/serializers/task_serializer.rb

@@ -0,0 +1,6 @@
+class TaskSerializer
+  include JSONAPI::Serializer
+  attributes :name, :description, :user_id, :activity_id
+
+  cache_options store: Rails.cache, namespace: 'jsonapi-serializer', expires_in: 1.hour
+end