PERF: automatic upload size calculation not persisted

Previously if upload had missing width and height we would calculate
on first use BUT we (me) forgot to save this to the database

This was particularly bad on home page cause category images (when old)
miss dimensions.

app/models/upload.rb

@@ -126,8 +126,19 @@ class Upload < ActiveRecord::Base
       end
 
     begin
-      self.width, self.height = size = FastImage.new(path, raise_on_failure: true).size
-      self.thumbnail_width, self.thumbnail_height = ImageSizer.resize(*size)
+      w, h = FastImage.new(path, raise_on_failure: true).size
+
+      self.width = w || 0
+      self.height = h || 0
+
+      self.thumbnail_width, self.thumbnail_height = ImageSizer.resize(w, h)
+
+      self.update_columns(
+        width: width,
+        height: height,
+        thumbnail_width: thumbnail_width,
+        thumbnail_height: thumbnail_height
+      )
     rescue => e
       Discourse.warn_exception(e, message: "Error getting image dimensions")
     end

spec/models/upload_spec.rb

@@ -55,6 +55,9 @@ describe Upload do
     expect(upload.width).to eq(64250)
     expect(upload.height).to eq(64250)
 
+    upload.reload
+    expect(upload.read_attribute(:width)).to eq(64250)
+
     upload.update_columns(width: nil, height: nil, thumbnail_width: nil, thumbnail_height: nil)
 
     expect(upload.thumbnail_width).to eq(500)