Initial implementation of friend chat

@mikeymurph77 @ChristopherThorsen 
you don't want to interpolate inside of strings that are used for sql queries. this is very unsafe because the strings are unescaped, meaning people could run arbitrary code if you interpolated user input. While this isn't user input, I wouldn't get in the habit of this. read section 2.2 here: http://guides.rubyonrails.org/active_record_querying.html#array-conditions