Add posts, tags, tagging, to database. Create references to align with new DB model. Add image of mermaid template model.

app/models/image.rb

@@ -1,5 +1,8 @@
 class Image < ApplicationRecord
   has_one_attached :file
 
+  has_many :taggings, as: :taggable
+  has_many :tags, through: :taggings
+
   validates :title, :file, presence: true
 end

app/models/post.rb

@@ -0,0 +1,6 @@
+class Post < ApplicationRecord
+  belongs_to :user
+  belongs_to :image
+  has_many :taggings, as: :taggable
+  has_many :tags, through: :taggings
+end

app/models/tag.rb

@@ -0,0 +1,5 @@
+class Tag < ApplicationRecord
+  has_many :taggings
+  has_many :posts, through: :taggings, source: :taggable, source_type: "Post"
+  has_many :images, through: :taggings, source: :taggable, source_type: "Image"
+end

app/models/tagging.rb

@@ -0,0 +1,4 @@
+class Tagging < ApplicationRecord
+  belongs_to :tag
+  belongs_to :taggable, polymorphic: true
+end

app/models/user.rb

@@ -1,3 +1,6 @@
 class User < ApplicationRecord
   has_secure_password
+  has_many :posts
+
+  validates :name, :status, :email, :password_digest, presence: true
 end