Why God created the rainbow ?

I woke up in Church today and finally had a good and satisfying sleep, we had a gathering in the church, its our spiritual retreat. and together with my girlfriend. its a retreat so therefore we should settle all our arguments and have fun. i will be going home this afternoon and i miss my family. No DOTA today, so much of that tiring game, you'll be beaten hard anyway lol. Why God created the rainbow was the title because we had a group activity and that was the question that was give to me, scientificaly. its all about the tiny little droplets of water that was reflected by the suns ray and thus giving its roy g. biv appearace. in the bibile its simple a remembrance of God's covenant to us according to our retreat master. and i believe, from noah's story which was my own favourite since i was a child. in literature, it was said that at the end of a rainbow is a pot of gold, which is a metapohr for something else., you should follow that rainbow and get the price. which ios simply striving hard to reach your goal.