Update Dockerfile

Author: sweoggy

Dockerfile

@@ -9,7 +9,7 @@ RUN groupadd -r mysql && useradd -r -g mysql mysql
 ENV APT_KEY_DONT_WARN_ON_DANGEROUS_USAGE=1
 RUN apt install software-properties-common dirmngr -y \
     && apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 0xF1656F24C74CD1D8 \
-    && add-apt-repository 'deb [arch=amd64,i386,ppc64el] http://ftp.ddg.lth.se/mariadb/repo/10.3/debian stretch main'
+    && add-apt-repository 'deb [arch=amd64,i386,ppc64el] http://ftp.ddg.lth.se/mariadb/repo/10.3/debian stretch main' \
     && { \
 		echo 'Package: *'; \
 		echo 'Pin: release o=MariaDB'; \