diff --git a/Data/Average top scorers.csv b/Data/Average top scorers.csv
index 2cd01eb..f0fe906 100644
--- a/Data/Average top scorers.csv	
+++ b/Data/Average top scorers.csv	
@@ -1,4 +1,4 @@
-Season,Average goals by top 3 players,Country
+Season,Average_goals_by_top_3_players,Country
 1999–20,24.333333333333332,England
 2000–01,19.666666666666668,England
 2001–02,23.333333333333332,England
diff --git a/Data/Market values.csv b/Data/Market values.csv
index e282ae2..e41ab8a 100644
--- a/Data/Market values.csv	
+++ b/Data/Market values.csv	
@@ -1,4 +1,4 @@
-Season,Gini coefficient,Average market value of clubs,Country
+Season,Gini_coefficient,Average market value of clubs,Country
 2004–05,0.360018498852386,116763999.95,England
 2005–06,0.3442440170940171,117000000.0,England
 2006–07,0.37966666666666665,125249999.9,England
diff --git a/Dockerfile b/Dockerfile
index a524af4..d215719 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -48,6 +48,13 @@ COPY . /srv/shiny-server/
 # Permissions
 RUN chown -R shiny:shiny /srv/shiny-server
 
+# Fail the image build if the app cannot start in the same user context as
+# Shiny Server, rather than discovering startup errors after deployment.
+RUN su -s /bin/sh shiny -c "cd /srv/shiny-server && R --vanilla -e 'source(\".Rprofile\"); source(\"global.R\")'"
+
 EXPOSE 3838
 
+HEALTHCHECK --interval=30s --timeout=5s --start-period=90s --retries=3 \
+  CMD curl --fail --silent --show-error http://127.0.0.1:3838/ || exit 1
+
 CMD ["/usr/bin/shiny-server"]
\ No newline at end of file