Add compilation test to githook (#181)

.githooks/pre-push

@@ -5,11 +5,30 @@ echo "------------"
 
 git stash -q --keep-index
 
-./gradlew spotlessCheck
+echo "--------------------"
+echo "Compiling classes..."
+echo "--------------------"
+
+./gradlew assemble
+compile_status=$?
 
-status=$?
+if [ "$compile_status" = 0 ] ; then
+    echo "Classes compiled successfully."
+else
+    echo "------------"
+    echo 1>&2 "Compilation of classes failed."
+    echo "Fix the compilation issues before trying to push again."
+    echo "------------"
+fi
+
+echo "--------------------"
+echo "Running spotless..."
+echo "--------------------"
+
+./gradlew spotlessCheck
+spotless_status=$?
 
-if [ "$status" = 0 ] ; then
+if [ "$spotless_status" = 0 ] ; then
     echo "Static analysis found no problems."
 else
     echo "------------"
@@ -20,4 +39,4 @@ fi
 
 git stash pop -q
 
-exit $status
+exit $((spotless_status + compile_status))