fix startup and drop 18.12 tag build

Dockerfile

@@ -13,6 +13,9 @@ RUN apt-get update && apt-get install -y \
   php7.2-json \
   php7.2-pgsql \
   php7.2-mysql \
+  php7.2-intl \
+  php7.2-mbstring \
+  php7.2-xml \
   curl \
   && apt-get clean && rm -rf /var/lib/apt/lists/*
 
@@ -31,8 +34,9 @@ WORKDIR /var/www
 #    && apt-get purge -y --auto-remove curl \
 
 RUN curl -SL https://git.tt-rss.org/git/tt-rss/archive/$TTRSS_GIT_TAG.tar.gz | tar xzC /var/www --strip-components 1 \
+    && cp config.php-dist config.php \
     && chown www-data:www-data -R /var/www \
-    && cp config.php-dist config.php
+    && mkdir /var/run/php
 
 # expose only nginx HTTP port
 EXPOSE 80