Fix font kerning in container

See: wkhtmltopdf/wkhtmltopdf#45

Dockerfile

@@ -9,6 +9,7 @@ RUN rm -rf wkhtmltox
 
 RUN cp -r ./fonts/liberation_sans /usr/share/fonts/truetype/
 RUN fc-cache -f -v
+RUN cp ./fonts/10-wkhtmltopdf.conf /etc/fonts/conf.d/
 
 ENV UNICORN_PORT 3000
 EXPOSE $UNICORN_PORT

fonts/10-wkhtmltopdf.conf

@@ -0,0 +1,29 @@
+<?xml version='1.0'?>
+<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
+<fontconfig>
+ <match target="font">
+  <edit mode="assign" name="rgba">
+   <const>rgb</const>
+  </edit>
+ </match>
+ <match target="font">
+  <edit mode="assign" name="hinting">
+   <bool>true</bool>
+  </edit>
+ </match>
+ <match target="font">
+  <edit mode="assign" name="hintstyle">
+   <const>hintslight</const>
+  </edit>
+ </match>
+ <match target="font">
+  <edit mode="assign" name="antialias">
+   <bool>true</bool>
+  </edit>
+ </match>
+  <match target="font">
+    <edit mode="assign" name="lcdfilter">
+      <const>lcddefault</const>
+    </edit>
+  </match>
+</fontconfig>