Distribution of restaurant grades

grades.R

# Shiny Server Code to render distribution of grades plot 

output$grade_plot <- renderGvis({
    # transform data for GoogleVis: group by year and grade
    grade_only_grouped <- grade_data()%>%
      group_by(year,grade)%>%
      summarise(n=n())
    
    #melt and cast data into the format for stacked googlevis 
    mgrade_only <- melt(grade_only_grouped, id = c("grade","year"))
    grade_dist <- cast(mgrade_only, year~grade,sum)
    
    gvisColumnChart(grade_dist, options = list(
      isStacked="percent", colors="['#A6D0BD','#565656','red']"))
})