How to translate "define , commit , and private beta"? In the area 51 SE, when sites are still in testing mode. How would one translate the words define, commit, and private beta? 

This idea was originally brought up by another user who wanted to start an SE to appeal to the Chinese users. 

I'm thinking 
define can be translated as 定義 (definition)
commit I'm not so sure
Private beta as beta 測試 or maybe use execute (verb) like 執行階段

or maybe there is a better way to present these terms like 定義階段, commitment 階段, 測試階段/執行階段

What are good translations for "define , commit , and private beta" in the context of SE?
I agree define is 定義階段 and beta is 測試階段. And commit, I suggest that is translated as 推行階段 which means promote because the commit stage needs someone's promotion by commit.