fix: Correct COPY path for image build

Dockerfile

@@ -19,7 +19,7 @@ RUN API_URL=$API_URL node scripts/build.js
 FROM node:12.16.3
 
 WORKDIR "/usr/app"
-COPY package*.json .
+COPY ./app/server/package*.json .
 RUN npm install --production
 COPY ./app/server .
 # Copy client app into public folder