Linear Regression - Append Predicted Values to Same dataset

I recently started with R programming. This is my dataset

WeekOfYear  Production
         1      202612
         2      245633
         3      299653
         4      252612
         5      299633
         6      288993
         7      254653
         8      288612
         9      277733
        10      245633

I need to predict “Production” values for the remaining Weeks of the Year

relation<-lm(Production~WeekOfYear,dataset)

predict(relation,data.frame(WeekOfYear=c(11)))

How to append predicted values for week nos 11 to 52 (end of year) to the same dataset like below

WeekOfYear  Production
        1       202612
        2       245633
        3       299653
        4       252612
        5       299633
        6       288993
        7       254653
        8       288612
        9       277733
       10       245633
       11   predicted value
       12   predicted value

so on

-OR-

WeekOfYear  Production  Regression
         1      202612  fitted value
         2      245633  fitted value
         3      299653  fitted value
         4      252612  fitted value
         5      299633  fitted value
         6      288993  fitted value
         7      254653  fitted value
         8      288612  fitted value
         9      277733  fitted value
        10      245633  fitted value
        11              predicted value
        12              predicted value
        13              predicted value
        14              predicted value
         .
         .
        52              predicted value