add aspect ratio to the manga card. (#56)

* added an aspect ratio to the manga card.

* added a comment and chaged the ratio to the recommeded

src/components/MangaCard.tsx

@@ -17,9 +17,11 @@ import SpinnerImage from 'components/util/SpinnerImage';
 
 const useStyles = makeStyles((theme) => ({
     root: {
-        height: '100%',
-        width: '100%',
         display: 'flex',
+        // Preserve the shape of the manga cards, without this the manga card would chage it's
+        // if all the images in a row failed to load then the whole row would change into a
+        //  square shape
+        aspectRatio: '225/350',
     },
     wrapper: {
         position: 'relative',