diff --git a/Makefile b/Makefile
index eeb2ead..3bbe610 100644
--- a/Makefile
+++ b/Makefile
@@ -29,7 +29,7 @@ $(TARGET): $(OBJS)
 	$(CROSS_COMPILE)$(CC) $(CFLAGS) $(INCLUDES) -c $< -o $@
 
 clean:
-	rm -f $(OBJS) $(TARGET) $(shell find . -type f -name '*.log') users.db
+	rm -f $(OBJS) $(TARGET) $(shell find . -type f -name '*.log') users.db users_db.json
 
 test: $(TARGET)
 	bash ./tests.sh
diff --git a/src/db_get_user_by_id.c b/src/db_get_user_by_id.c
index 5c7448e..033ecd4 100644
--- a/src/db_get_user_by_id.c
+++ b/src/db_get_user_by_id.c
@@ -1,3 +1,4 @@
+#include "cJSON.h"
 #include "database.h"
 #include "sql.h"
 #include "user.h"
@@ -68,9 +69,15 @@ User *db_get_user_by_id(const int id) {
   }
   if (found == nullptr) {
     pthread_mutex_unlock(&users_file_mutex);
+    // if (user != nullptr) cJSON_Delete(user);
+    cJSON_Delete(users);
+    free(data);
     return nullptr;
   }
   pthread_mutex_unlock(&users_file_mutex);
+  // if (user != nullptr) cJSON_Delete(user);
+  cJSON_Delete(users);
+  free(data);
   return found;
 #endif
 }
diff --git a/src/db_get_user_by_username.c b/src/db_get_user_by_username.c
index 8063c8f..5f14757 100644
--- a/src/db_get_user_by_username.c
+++ b/src/db_get_user_by_username.c
@@ -69,9 +69,15 @@ User *db_get_user_by_username(const char *username) {
   }
   if (found == nullptr) {
       pthread_mutex_unlock(&users_file_mutex);
+      // if (user != nullptr) cJSON_Delete(user);
+      cJSON_Delete(users);
+      free(data);
       return nullptr;
   }
   pthread_mutex_unlock(&users_file_mutex);
+  // if (user != nullptr) cJSON_Delete(user);
+  cJSON_Delete(users);
+  free(data);
   return found;
 #endif
 }
diff --git a/src/db_get_user_field_by_id.c b/src/db_get_user_field_by_id.c
index d1e57d9..378e782 100644
--- a/src/db_get_user_field_by_id.c
+++ b/src/db_get_user_field_by_id.c
@@ -70,9 +70,15 @@ char *db_get_user_field_by_id(const int id, const char *field) {
   }
   if (found == nullptr) {
     pthread_mutex_unlock(&users_file_mutex);
+    // if (user != nullptr) cJSON_Delete(user);
+    cJSON_Delete(users);
+    free(data);
     return nullptr;
   }
   pthread_mutex_unlock(&users_file_mutex);
+  // if (user != nullptr) cJSON_Delete(user);
+  cJSON_Delete(users);
+  free(data);
   return found->password;
 #endif
 }
diff --git a/src/db_insert_user.c b/src/db_insert_user.c
index 55d62e5..d53d0db 100644
--- a/src/db_insert_user.c
+++ b/src/db_insert_user.c
@@ -70,29 +70,25 @@ User *db_insert_user(const char *username, const char *email,
   pthread_mutex_lock(&users_file_mutex);
   char *data = read_file("users_db.json");
   cJSON *users = cJSON_Parse(data);
-  char *old_data = cJSON_Print(users);
-  if (old_data == NULL) {
-      printf("ERR");
-  }
   cJSON *user = nullptr;
   int users_size = 0;
-  User *found = nullptr;
+  bool found = false;
   cJSON_ArrayForEach(user, users) {
-    cJSON *user_id = cJSON_GetObjectItem(user, "id");
     cJSON *user_username = cJSON_GetObjectItem(user, "username");
     cJSON *user_password = cJSON_GetObjectItem(user, "password");
     cJSON *user_email = cJSON_GetObjectItem(user, "email");
     cJSON *user_group = cJSON_GetObjectItem(user, "group");
-    cJSON *user_is_superuser = cJSON_GetObjectItem(user, "is_superuser");
-    if (!strcmp(user_username->valuestring, username)) {
-      found = new_user(user_id->valueint, user_username->valuestring,
-                       user_password->valuestring, user_email->valuestring,
-                       user_group->valuestring, user_is_superuser->valueint);
+    if (!strcmp(user_username->valuestring, username) &&
+        !strcmp(user_password->valuestring, password) &&
+        !strcmp(user_email->valuestring, email) &&
+        !strcmp(user_group->valuestring, group)) {
+      found = true;
     }
     users_size++;
   }
-  if (found != nullptr) {
-      return nullptr;
+  if (found == true) {
+    pthread_mutex_unlock(&users_file_mutex);
+    return nullptr;
   }
   cJSON *new_user_data = cJSON_CreateObject();
   cJSON *new_user_id = cJSON_CreateNumber(users_size);
@@ -100,7 +96,7 @@ User *db_insert_user(const char *username, const char *email,
   cJSON *new_user_password = cJSON_CreateString(password);
   cJSON *new_user_email = cJSON_CreateString(email);
   cJSON *new_user_group = cJSON_CreateString(group);
-  cJSON *new_user_is_superuser = cJSON_CreateBool(*is_superuser);
+  cJSON *new_user_is_superuser = cJSON_CreateBool(is_superuser?1:0);
   cJSON_AddItemToObject(new_user_data, "id", new_user_id);
   cJSON_AddItemToObject(new_user_data, "username", new_user_username);
   cJSON_AddItemToObject(new_user_data, "password", new_user_password);
@@ -108,20 +104,20 @@ User *db_insert_user(const char *username, const char *email,
   cJSON_AddItemToObject(new_user_data, "group", new_user_group);
   cJSON_AddItemToObject(new_user_data, "is_superuser", new_user_is_superuser);
   char *new_user_data_string = cJSON_Print(new_user_data);
-  printf("%s\n", new_user_data_string);
   if (users_size == 0) {
-      users = cJSON_CreateArray();
+    users = cJSON_CreateArray();
   }
   cJSON_AddItemToArray(users, new_user_data);
   char *new_data = cJSON_Print(users);
-  if (new_data == NULL) {
-      printf("ERR");
-  }
-  // printf("%s\n", strdup(new_data));
-  // write_file("users_db.json", new_data);
-  free(new_data);
+  write_file("users_db.json", new_data);
   pthread_mutex_unlock(&users_file_mutex);
-  User *return_user = new_user(users_size, username, email, password, group, is_superuser);
+  User *return_user =
+      new_user(users_size, username, email, password, group, is_superuser);
+  free(new_data);
+  free(data);
+  free(new_user_data_string);
+  cJSON_Delete(new_user_data);
+  if (user != nullptr) cJSON_Delete(user);
   return return_user;
 #endif
 }
diff --git a/src/file.c b/src/file.c
index c0488c8..d9f21db 100644
--- a/src/file.c
+++ b/src/file.c
@@ -1,10 +1,14 @@
 #include "file.h"
 
+#include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 char *read_file(const char *path) {
+  create_file_if_not_exists(path);
   FILE *fp = fopen(path, "rb");
   if (fp == NULL) {
     perror("Error opening file");
@@ -36,6 +40,7 @@ char *read_file(const char *path) {
 }
 
 char *write_file(const char *path, const char *data) {
+  create_file_if_not_exists(path);
   FILE *fp = fopen(path, "w");
   if (fp == NULL) {
     printf("%s\n", path);
@@ -50,3 +55,23 @@ char *write_file(const char *path, const char *data) {
   char *ret = strdup(data);
   return ret;
 }
+
+int create_file_if_not_exists(const char *filename) {
+  if (!check_file_exists(filename)) {
+    return 0;
+  }
+  FILE *file = fopen(filename, "w");
+  if (file == nullptr) {
+    perror("Error creating file");
+    return -1;
+  }
+  fclose(file);
+  return 0;
+}
+
+int check_file_exists(const char *filename) {
+  if (access(filename, F_OK) == 0) {
+    return 0;
+  }
+  return -1;
+}
diff --git a/src/file.h b/src/file.h
index 9ac6d5d..817f267 100644
--- a/src/file.h
+++ b/src/file.h
@@ -2,3 +2,5 @@
 
 char *read_file(const char *path);
 char *write_file(const char *path, const char *data);
+int create_file_if_not_exists(const char *filename);
+int check_file_exists(const char *filename);