Rmarkdown file won't run code chunk with ggplot2 after knitting

[Callan_Lutz]

Hello, I am in the process of finishing an rmd file as a report for a project. Everything so far has worked as intended, but I am unable to load a plot that is embedded into the file after knitting it. So if I run the code chunk before I knit the file, it produces the plot correctly as expected. But when I knit the file, the final product fails to render and tells me there is an error.
Here is what the code chunk for the plot looks like:

q4_2016_v2 %>% 
  mutate(weekday = wday(started_at, label = TRUE)) %>% 
  group_by(member_casual, weekday) %>% 
  summarise(number_of_rides = n()
            ,average_duration = mean(ride_length)) %>% 
  arrange(member_casual, weekday)  %>% 
  ggplot(aes(x = weekday, y = number_of_rides, fill = member_casual)) +
  geom_col(position = "dodge") +
  labs(title="Number of Rides per Day of the Week",
      subtitle="Sample of Cyclistic Members and Casual users", 
	caption="Data collected from Cyclistic Bikes",
	y='Number of Rides',
	x='Day of the Week',
	fill = "Type of User")

Here is the error I receive:

processing file: Data-Analytics-Capstone-Report.Rmd
  |..............................                      |  57% [unnamed-chunk-1]
Quitting from lines 259-273 [unnamed-chunk-1] (Data-Analytics-Capstone-Report.Rmd)
                                                                                                            
Error in `q4_2016_v2 %>% mutate(weekday = wday(started_at, label = TRUE)) %>% group_by(
    member_casual, weekday) %>% summarise(number_of_rides = n(),
  average_duration = mean(ride_length)) %>% arrange(member_casual, weekday) %>%
    ggplot(aes(x = weekday, y = number_of_rides, fill = member_casual))`:
! could not find function "%>%"
Execution halted

The lines listed (259-273) match up with the code chunk above. In this report I have listed all the steps I took to get to the final code chunk above, but none of them are set to run when rendered (using the {r}). I noticed that the knit couldn't find the %>% function, so I went to where I loaded the packages and had them run when rendered, but got another error. I don't know if that is where the problem is but this is the error for that:

processing file: Data-Analytics-Capstone-Report.Rmd
  |.......................                             |  44% [unnamed-chunk-1]
Quitting from lines 33-40 [unnamed-chunk-1] (Data-Analytics-Capstone-Report.Rmd)
Error in `contrib.url()`:
! trying to use CRAN without setting a mirror
Backtrace:
 1. utils::install.packages("tidyverse")
 2. utils::contrib.url(repos, "source")
                                                                                                            
Execution halted

Any help would be great.

[startz]

Remember that R Markdown runs in its own environment. You probably have a library loaded that works when you run the code chunk that isn't actually loaded in the R Markdown file.

[M_AcostaCH]

When I work with Rmd I'm like to try to load all libraries testing in the first chunk for avoid this errors. It`s a good practice.