diff --git a/internal/adapters/db/user.go b/internal/adapters/db/user.go
index f91540a..7340204 100644
--- a/internal/adapters/db/user.go
+++ b/internal/adapters/db/user.go
@@ -1,6 +1,7 @@
 package db
 
 type User struct {
+	ID       int
 	Nickname string
 	Password string
 }
diff --git a/internal/adapters/rest/middleware/authmiddleware.go b/internal/adapters/rest/middleware/authmiddleware.go
index cf74b26..6d013d5 100644
--- a/internal/adapters/rest/middleware/authmiddleware.go
+++ b/internal/adapters/rest/middleware/authmiddleware.go
@@ -2,6 +2,7 @@ package middleware
 
 import (
 	"github.com/gin-gonic/gin"
+	"github.com/pangolin-do-golang/thumb-processor-api/internal/core/users"
 	"net/http"
 )
 
@@ -21,6 +22,10 @@ func AuthMiddleware(allowedUsersFunc func() gin.Accounts) gin.HandlerFunc {
 			return
 		}
 
+		loggedUser := users.GetUserByNickname(username)
+
+		c.Set("logged_user_id", loggedUser.ID)
+
 		c.Next() // Continue to the handler
 	}
 }
diff --git a/internal/adapters/rest/middleware/authmiddleware_test.go b/internal/adapters/rest/middleware/authmiddleware_test.go
index c0d0dd5..ebe9bdb 100644
--- a/internal/adapters/rest/middleware/authmiddleware_test.go
+++ b/internal/adapters/rest/middleware/authmiddleware_test.go
@@ -22,9 +22,9 @@ func TestAuthMiddleware(t *testing.T) {
 	}{
 		{
 			name:             "Valid Credentials",
-			username:         "testuser",
+			username:         "test",
 			password:         "testpassword",
-			allowedUsersFunc: func() gin.Accounts { return gin.Accounts{"testuser": "testpassword"} },
+			allowedUsersFunc: func() gin.Accounts { return gin.Accounts{"test": "testpassword"} },
 			expectedStatus:   http.StatusOK, // Or 200 if you're checking for a successful continuation
 			expectedMessage:  "",            // No message expected on success
 		},
diff --git a/internal/core/users/users.go b/internal/core/users/users.go
index 760f7d2..1e1cfa1 100644
--- a/internal/core/users/users.go
+++ b/internal/core/users/users.go
@@ -3,12 +3,13 @@ package users
 import (
 	"github.com/gin-gonic/gin"
 	"github.com/pangolin-do-golang/thumb-processor-api/internal/adapters/db"
+	"math/rand"
 )
 
 var users = []db.User{
-	{Nickname: "user", Password: "user"},
-	{Nickname: "test", Password: "test"},
-	{Nickname: "prod", Password: "prod"},
+	{ID: 1, Nickname: "user", Password: "user"},
+	{ID: 2, Nickname: "test", Password: "test"},
+	{ID: 3, Nickname: "prod", Password: "prod"},
 }
 
 func GetAllowedUsers() gin.Accounts {
@@ -20,5 +21,14 @@ func GetAllowedUsers() gin.Accounts {
 }
 
 func CreateUser(nickname, password string) {
-	users = append(users, db.User{Nickname: nickname, Password: password})
+	users = append(users, db.User{ID: rand.Int(), Nickname: nickname, Password: password})
+}
+
+func GetUserByNickname(nickname string) *db.User {
+	for _, user := range users {
+		if user.Nickname == nickname {
+			return &user
+		}
+	}
+	return nil
 }
diff --git a/internal/core/users/users_test.go b/internal/core/users/users_test.go
index 509519f..914999f 100644
--- a/internal/core/users/users_test.go
+++ b/internal/core/users/users_test.go
@@ -52,3 +52,54 @@ func TestCreateUser(t *testing.T) {
 		{Nickname: "prod", Password: "prod"},
 	}
 }
+
+func TestGetUserByNickname(t *testing.T) {
+	// Test case 1: User exists
+	existingUser := "user"
+	user := GetUserByNickname(existingUser)
+
+	if user == nil {
+		t.Errorf("GetUserByNickname(%s) returned nil, expected a user", existingUser)
+	} else if user.Nickname != existingUser {
+		t.Errorf("GetUserByNickname(%s) returned user with nickname %s, expected %s", existingUser, user.Nickname, existingUser)
+	}
+
+	// Test case 2: User does not exist
+	nonExistingUser := "nonexistent"
+	user = GetUserByNickname(nonExistingUser)
+
+	if user != nil {
+		t.Errorf("GetUserByNickname(%s) returned a user, expected nil", nonExistingUser)
+	}
+
+	// Test case 3: Empty nickname
+	emptyNickname := ""
+	user = GetUserByNickname(emptyNickname)
+
+	if user != nil {
+		t.Errorf("GetUserByNickname(%s) returned a user, expected nil", emptyNickname)
+	}
+
+	// Test case 4: Check if the returned user is a copy, not a reference to the original slice
+	originalUsers := users // Keep a copy of the original users slice
+
+	testNickname := "test_copy"
+	testPassword := "password_copy"
+	CreateUser(testNickname, testPassword) // Add a new user
+
+	retrievedUser := GetUserByNickname(testNickname)
+	if retrievedUser == nil {
+		t.Errorf("GetUserByNickname(%s) returned nil, expected a user", testNickname)
+	}
+
+	retrievedUser.Password = "modified_password" // Modify the retrieved user's password
+
+	originalRetrievedUser := GetUserByNickname(testNickname) //Get again the user
+
+	if originalRetrievedUser.Password == "modified_password" {
+		t.Errorf("GetUserByNickname returned a pointer to the original user in the slice. Should return a copy")
+	}
+	
+	users = originalUsers
+
+}