added database

src/sql.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#define CREATE_TABLE_USERS               \
+  "create table if not exists users("    \
+  "id integer primary key autoincrement,"    \
+  "username text unique,"                \
+  "email char(50) unique,"               \
+  "password char(150) not null,"         \
+  "user_group char(50) default 'users'," \
+  "is_superuser boolean default false"   \
+  ");"
+
+#define INSERT_USER_SQL                                                      \
+  "INSERT INTO users (username, email, password, user_group, is_superuser) " \
+  "VALUES (?, ?, ?, ?, ?)"
+
+#define SELECT_ALL_USERS_SQL "select * from users"
+#define SELECT_USER_BY_USERNAME_SQL "select * from users where username = ?"
+