Set TEXMFVAR to a writable location (#739)

Dockerfile-base

@@ -7,6 +7,11 @@ FROM phusion/baseimage:0.11
 ENV baseDir .
 
 
+# Makes sure LuaTex cache is writable
+# -----------------------------------
+ENV TEXMFVAR=/var/lib/sharelatex/tmp/texmf-var
+
+
 # Install dependencies
 # --------------------
 RUN apt-get update \

docker-compose.yml

@@ -39,7 +39,7 @@ services:
 
             # Enables Thumbnail generation using ImageMagick
             ENABLE_CONVERSIONS: 'true'
-            
+
             # Disables email confirmation requirement
             EMAIL_CONFIRMATION_DISABLED: 'true'