removes user_id column from User model to use idiomatic Rails automatic IDs

app/models/message.rb

@@ -4,7 +4,7 @@ class Message < ApplicationRecord
   validates_presence_of :creator_id, :receiver_id, :message
 
   def creator_name
-    if creator = User.where(user_id: self.creator_id).first
+    if creator = User.where(id: self.creator_id).first
       creator.full_name
     else
       "Name unavailable"

app/models/user.rb

@@ -10,17 +10,17 @@ class User < ApplicationRecord
 
   validates_presence_of :email
   validates_uniqueness_of :email
-  validates_format_of :email, with: /.+@.+\..+/i
-  attr_accessor :skip_user_id_assign
-  before_save :assign_user_id, on: :create
+  validates_format_of :email, :with => /.+@.+\..+/i
+
+  has_one :retirement, dependent: :destroy
+  has_one :paid_time_off, dependent: :destroy
+  has_one :work_info, dependent: :destroy
+  has_many :performance, dependent: :destroy
+  has_many :pay, dependent: :destroy
+  has_many :messages, foreign_key: :receiver_id, dependent: :destroy
+
   before_save :hash_password
-  has_one :retirement, foreign_key: :user_id, primary_key: :user_id, dependent: :destroy
-  has_one :paid_time_off, foreign_key: :user_id, primary_key: :user_id, dependent: :destroy
-  has_one :work_info, foreign_key: :user_id, primary_key: :user_id, dependent: :destroy
-  has_many :performance, foreign_key: :user_id, primary_key: :user_id, dependent: :destroy
-  has_many :messages, foreign_key: :receiver_id, primary_key: :user_id, dependent: :destroy
-  has_many :pay, foreign_key: :user_id, primary_key: :user_id, dependent: :destroy
-  before_create { generate_token(:auth_token) }
+  after_create { generate_token(:auth_token) }
   before_create :build_benefits_data
 
   def build_benefits_data
@@ -36,11 +36,6 @@ class User < ApplicationRecord
     "#{self.first_name} #{self.last_name}"
   end
 
-#   # Instead of the entire user object being returned, we can use this to filter.
-#   def as_json
-#     super(only: [:user_id, :email, :first_name, :last_name])
-#   end
-
   private
 
   def self.authenticate(email, password)
@@ -55,26 +50,17 @@ class User < ApplicationRecord
     return auth
   end
 
-  def assign_user_id
-    unless @skip_user_id_assign.present? || self.user_id.present?
-      user = User.order("user_id").last
-      uid = if user && user.user_id && !(User.exists?(user_id: "#{user.user_id.to_i + 1}"))
-              user.user_id.to_i + 1
-            else
-              1
-            end
-      self.user_id = uid.to_s if uid
-    end
-  end
-
   def hash_password
-    if password.present? && password_changed?
-      self.password = Digest::MD5.hexdigest(password)
+    if will_save_change_to_password?
+      self.password = Digest::MD5.hexdigest(self.password)
     end
   end
 
   def generate_token(column)
-    self[column] = Encryption.encrypt_sensitive_value(self.user_id)
-    generate_token(column) if User.exists?(column => self[column])
+    begin
+      self[column] = Encryption.encrypt_sensitive_value(self.id)
+    end while User.exists?(column => self[column])
+
+    self.save!
   end
 end