diff --git a/.gitignore b/.gitignore
index 7e6b54f..03a21a9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -31,3 +31,4 @@
 
 # Ignore master key for decrypting credentials and more.
 /config/master.key
+.idea
\ No newline at end of file
diff --git a/Gemfile.lock b/Gemfile.lock
index 4ea1d96..91f9caf 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -158,15 +158,7 @@ GEM
     net-smtp (0.4.0.1)
       net-protocol
     nio4r (2.7.0)
-    nokogiri (1.16.2-aarch64-linux)
-      racc (~> 1.4)
-    nokogiri (1.16.2-arm-linux)
-      racc (~> 1.4)
-    nokogiri (1.16.2-arm64-darwin)
-      racc (~> 1.4)
-    nokogiri (1.16.2-x86-linux)
-      racc (~> 1.4)
-    nokogiri (1.16.2-x86_64-darwin)
+    nokogiri (1.16.2-x64-mingw-ucrt)
       racc (~> 1.4)
     nokogiri (1.16.2-x86_64-linux)
       racc (~> 1.4)
@@ -176,6 +168,7 @@ GEM
       ast (~> 2.4.1)
       racc
     pg (1.5.4)
+    pg (1.5.4-x64-mingw-ucrt)
     psych (5.1.2)
       stringio
     public_suffix (5.0.4)
@@ -288,6 +281,8 @@ GEM
     timeout (0.4.1)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
+    tzinfo-data (1.2024.1)
+      tzinfo (>= 1.0.0)
     unicode-display_width (2.5.0)
     warden (1.2.9)
       rack (>= 2.0.9)
@@ -303,11 +298,7 @@ GEM
     zeitwerk (2.6.13)
 
 PLATFORMS
-  aarch64-linux
-  arm-linux
-  arm64-darwin
-  x86-linux
-  x86_64-darwin
+  x64-mingw-ucrt
   x86_64-linux
 
 DEPENDENCIES
diff --git a/app/models/car.rb b/app/models/car.rb
index ce30b91..7db191f 100644
--- a/app/models/car.rb
+++ b/app/models/car.rb
@@ -1,2 +1,9 @@
 class Car < ApplicationRecord
+  has_many :reservations, dependent: :destroy
+  has_one :car_detail, dependent: :destroy
+
+  accepts_nested_attributes_for :car_detail
+
+  validates :name, presence: true, length: { minimum: 3, maximum: 255 }
+  validates :description, presence: true, length: { minimum: 10, maximum: 255 }
 end
diff --git a/app/models/car_detail.rb b/app/models/car_detail.rb
index d39d79e..762d54e 100644
--- a/app/models/car_detail.rb
+++ b/app/models/car_detail.rb
@@ -1,4 +1,9 @@
 class CarDetail < ApplicationRecord
   belongs_to :car
   belongs_to :engine_type
+
+  validates :horsepower, :torque, numericality: { only_integer: true, greater_than: 0 }
+  validates :fuel_economy, :seating_capacity, :cargo_space, :infotainment_system, :safety_rating, :tech_features,
+            :special_features, presence: true
+  validates :fuel_economy, :cargo_space, length: { maximum: 255 }
 end
diff --git a/app/models/city.rb b/app/models/city.rb
index f2188b0..ad609fe 100644
--- a/app/models/city.rb
+++ b/app/models/city.rb
@@ -1,2 +1,5 @@
 class City < ApplicationRecord
+  has_many :reservations, dependent: :destroy
+
+  validates :name, presence: true, length: { minimum: 1, maximum: 255 }
 end
diff --git a/app/models/engine_type.rb b/app/models/engine_type.rb
index 8f0986e..b8a7e2c 100644
--- a/app/models/engine_type.rb
+++ b/app/models/engine_type.rb
@@ -1,2 +1,5 @@
 class EngineType < ApplicationRecord
+  has_many :car_details, dependent: :destroy
+
+  validates :name, presence: true, length: { maximum: 255 }
 end
diff --git a/app/models/reservation.rb b/app/models/reservation.rb
index 206c0c1..3f3548c 100644
--- a/app/models/reservation.rb
+++ b/app/models/reservation.rb
@@ -2,4 +2,11 @@ class Reservation < ApplicationRecord
   belongs_to :city
   belongs_to :car
   belongs_to :user
+
+  validates :date, presence: true
+  validate :date_cannot_be_in_the_past
+
+  def date_cannot_be_in_the_past
+    errors.add(:date, "can't be in the past") if date.present? && date < Date.today
+  end
 end
diff --git a/app/models/user.rb b/app/models/user.rb
index 610c923..6da926b 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -1,10 +1,11 @@
 class User < ApplicationRecord
+  has_many :reservations, dependent: :destroy
   include Devise::JWT::RevocationStrategies::JTIMatcher
 
   devise :database_authenticatable, :registerable, :recoverable, :validatable, :jwt_authenticatable,
          jwt_revocation_strategy: self
 
-  has_many :reservations
+  has_many :reservations, dependent: :destroy
 
   enum role: { user: 0, admin: 1 }