install with composer.lock to make sure exact versions are installed

.dockerignore

@@ -4,5 +4,4 @@ vendor
 data
 images
 thumbs
-composer.lock
 *.sqlite

Dockerfile

@@ -7,7 +7,7 @@ HEALTHCHECK --interval=5m --timeout=3s CMD curl --fail http://127.0.0.1:8000/ ||
 RUN apt install -y php7.3-cli php7.3-gd php7.3-pgsql php7.3-mysql php7.3-sqlite3 php7.3-zip php7.3-dom php7.3-mbstring php-xdebug
 RUN apt install -y composer imagemagick vim zip unzip
 
-COPY composer.json /app/
+COPY composer.json composer.lock /app/
 WORKDIR /app
 RUN composer install