adding pgsql support (#61)

php7-pdo_pgsql@commuedge \

rainloop/Dockerfile

@@ -20,8 +20,10 @@ RUN echo "@commuedge https://nl.alpinelinux.org/alpine/edge/community" >> /etc/a
     php7-json@commuedge \
     php7-zlib@commuedge \
     php7-pdo_mysql@commuedge \
+    php7-pdo_pgsql@commuedge \
     php7-pdo_sqlite@commuedge \
     php7-sqlite3@commuedge \
+
  && cd /tmp \
  && wget -q http://repository.rainloop.net/v2/webmail/rainloop-community-latest.zip \
  && wget -q http://repository.rainloop.net/v2/webmail/rainloop-community-latest.zip.asc \