fileinfo and json modules, write to cache/icons/lock directories

Dockerfile

@@ -18,8 +18,9 @@ RUN \
     php7-fpm \
     php7-session \
     php7-mbstring \
+    php7-json \
+    php7-fileinfo \
     tar
-RUN ln -sf /usr/bin/php7 /usr/bin/php
 
 EXPOSE 80 443
 
@@ -32,4 +33,9 @@ RUN tar -xzf /tmp/ttrss.tar.gz -C /var/lib
 
 COPY config.php /var/lib/tt-rss/config.php
 
+RUN \
+    chmod -R 777 /var/lib/tt-rss/cache && \
+    chmod -R 777 /var/lib/tt-rss/feed-icons && \
+    chmod -R 777 /var/lib/tt-rss/lock
+
 CMD php-fpm7 && nginx -g "daemon off;"