add models for Project, Task, Note, Category

app/models/project.rb

@@ -0,0 +1,8 @@
+class Project < ApplicationRecord
+  belongs_to :user
+  belongs_to :project_category
+  has_many :contacts, through: :user
+  has_many :tasks
+  has_many :notes
+  enum business_type: { type1: 0, type2: 1 }
+end