Function egg_mode::user::relation

pub fn relation<'a, F, T>(
    from: F, 
    to: T, 
    con_token: &Token, 
    access_token: &Token
) -> WebResponse<Relationship> where
    F: Into<UserID<'a>>,
    T: Into<UserID<'a>>, 

Lookup relationship settings between two arbitrary users.