add login logic

.vs/VSWorkspaceState.json

@@ -0,0 +1,6 @@
+{
+  "ExpandedNodes": [
+    ""
+  ],
+  "PreviewInSolutionExplorer": false
+}

.vs/jv-oop-lesson-0/v17/DocumentLayout.json

@@ -0,0 +1,12 @@
+{
+  "Version": 1,
+  "WorkspaceRootPath": "C:\\Users\\sofyh\\Source\\Repos\\jv-oop-lesson-0\\",
+  "Documents": [],
+  "DocumentGroupContainers": [
+    {
+      "Orientation": 0,
+      "VerticalTabListWidth": 256,
+      "DocumentGroups": []
+    }
+  ]
+}

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 +13,11 @@ public class AuthenticationService {
      * Return false in any other cases.
      */
     public boolean login(String email, String password) {
-        return false;
+        User user = UserService.findByEmail(email);
+        if (user != null && user.getPassword().equals(password)) {
+            return true;
+        } else {
+            return false;
+        }
     }
 }

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

@@ -14,7 +14,14 @@ 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) {
+    public static User findByEmail(String email) {
+        for (int i = 0; i < users.length; i++) {
+            if (users[i].getEmail().equals(email)) {
+                return users[i];
+            } else {
+                continue;
+            }
+        }
         return null;
     }
 }