I am working on a design where I can have flexible attributes for users and I am confused how to continue the design of the schema.

I made a table where I kept system needed information:

Table name: users

• id
• username
• password

Now, I wish to create a profile table and have one to one relation where all the other attributes in profile table such as email, first name, last name, etc. My question is: is there a way to add a third table in which profiles will be flexible? In other words, if my clients need to create a new attribute he/she won't need any customization to the code.