rfm: rfm_model fucntion
In CJB2014/rfm: This package create a rfm model for customers segmentation

Load data in to create model

1	rfm(df, n_freq = c(2:5), n_rec = c(2:5), n_mon = c(2:5), score = TRUE)

`df`	a data frame loaded with rfm_load or created previously
`n_freq`	an integer between 2 and 5 representing the number of quantile to create for the frequency
`n_rec`	an integer between 2 and 5 representing the number of quantile to create for the recency
`n_mon`	an interget between 2 and 5 representing the number of quantile to create for the monetary score
`score`	a logical default is TRUE which add a concatenated rfm score as a variable in the return object. If FALSE then the score will not be added