add verify

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

@@ -11,6 +11,8 @@ public class AuthenticationService {
      * Return false in any other cases.
      */
     public boolean login(String email, String password) {
-        return false;
+        return UserService.findByEmail(email)
+                .getPassword()
+                .equals(password);
     }
 }

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

@@ -14,7 +14,12 @@ public class UserService {
      * @return - user if his email is equal to passed email.
      * Return <code>null</code> if there is no suitable user
      */
-    public User findByEmail(String email) {
-        return null;
+    public static User findByEmail(String email) {
+        for (User u : users) {
+            if (email.equals(u.getEmail())) {
+                return u;
+            }
+        }
+        return new User("NoNe", "");
     }
 }