implemented login method and findByEmail method

src/main/java/mate/academy/model/User.java

@@ -12,7 +12,6 @@ public User(String email, String password) {
     public String getEmail() {
         return email;
     }
-
     public String getPassword() {
         return password;
     }

src/main/java/mate/academy/service/AuthenticationService.java

@@ -1,5 +1,7 @@
 package mate.academy.service;
 
+import mate.academy.model.User;
+
 public class AuthenticationService {
     /**
      * Imagine that some user wants to login to your site.
@@ -11,6 +13,10 @@ public class AuthenticationService {
      * Return false in any other cases.
      */
     public boolean login(String email, String password) {
+        User users = new User(email, password);
+        if (users.getPassword().equals(password) && email != null) {
+            return true;
+        }
         return false;
     }
 }

src/main/java/mate/academy/service/UserService.java

@@ -15,6 +15,11 @@ public class UserService {
      * Return <code>null</code> if there is no suitable user
      */
     public User findByEmail(String email) {
+        for (User user : users) {
+            if (user.getEmail().equals(email)) {
+                return user;
+            }
+        }
         return null;
     }
 }