text_field for join table metadata with HMT

Hello,

I am having trouble making a text_field that changes the attribute of a
column in a join table (made using has_many :through).

Here a summary of my code:

#Table
create_table thingstuff: thing_id, stuff_id, helpme

#Relationship
thing has_many stuffs :through thingstuff

#Code
for thing in @stuff.find(:all)
text_field "thing[thingstuff]", "helpme", :size => 2

So, of course, that doesn't work. What I want to do is change the
"helpme" attribute that is related to the "thing" and "stuff". There is
only 1 row in "thingstuff" that has a specific "thing" and "stuff".

Would someone shed light on this ordeal? I might be using the wrong
approach.

Create a boolean attribute that connects to a checkbox. Without any
specific info about your app it's difficult to give sugestions

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