While there are a lot of plugins that adds rating type of stars, I would suggest that you code your own. Mainly because most of these are very feature rich with things you will not need.
This is a relatively simple process:
Add a custom user metadata using
update_user_meta(), name it
Add a custom post meta value using
update_post_meta(). The string value will be the rating, for example,
4.5. Name it
Then add rating stars to your single.php using
When user selects their rating, you should update the user's
post_voted value and store the post's ID in the array, and then you should use their choice of rating and add a simple algorithm for the
Finally, on loading the page, do a check if the user's
posts_voted contains the ID of the post; if it does, disable the voting for this user.
Doesn't this sound a lot better than adding a random plugin that contains tons of unnecessary features?