What to have in the main table and what to have in meta_table?
the user_meta table should contain details about the fields that will be in the user table.

for example, user_meta will have rows for each field in the user table


user_meta
---------
user_field_name | data_type  | size  | extra params  
---------------------------------------------------
user_name       | varchar    | 220   | primary key  
password        |varchar     |220    |not null


while the user table will have rows containing every field stated in the user_meta
using the example above, the user table will have look like this


users
-----
user_name |password  
-------------------
user1     |password1  
user2     |password2
...