chore(Docker): add comments to explain the building steps (#1638)

docker/authserver/Dockerfile

@@ -1,5 +1,7 @@
 FROM ubuntu:bionic
 
+# install the required dependencies to run the authserver
 RUN apt update && apt install -y libmysqlclient-dev libssl-dev libace-6.* libace-dev;
 
+# run the authserver located in the directory "docker/authserver/bin" of the host machine
 CMD ["/azeroth-server/bin/authserver"]

docker/build/Dockerfile

@@ -1,7 +1,9 @@
 FROM ubuntu:bionic
 
+# install the required dependencies to compile AzerothCore
 RUN apt update && apt install -y git cmake make gcc g++ clang libmysqlclient-dev libssl-dev libbz2-dev libreadline-dev libncurses-dev libace-6.* libace-dev
 
+# copy the sources from the host machine to the Docker container
 ADD .git /azerothcore/.git
 ADD deps /azerothcore/deps
 ADD conf/config.cmake.dist /azerothcore/conf/config.cmake.dist
@@ -9,9 +11,15 @@ ADD src /azerothcore/src
 ADD CMakeLists.txt /azerothcore/CMakeLists.txt
 
 ENTRYPOINT  cd azerothcore/build && \
+            # run cmake
             cmake ../ -DCMAKE_INSTALL_PREFIX=/azeroth-server -DCMAKE_C_COMPILER=/usr/bin/clang -DCMAKE_CXX_COMPILER=/usr/bin/clang++ -DTOOLS=0 -DSCRIPTS=1 && \
+            # calculate the optimal number of threads
             MTHREADS=`grep -c ^processor /proc/cpuinfo`; MTHREADS=$(($MTHREADS + 2)) && \
+            # run compilation
             make -j $MTHREADS && \
             make install -j $MTHREADS && \
+            # copy the binary files "authserver" and "worldserver" files back to the host
+            # - the directories "/binworldserver" and "/binauthserver" are meant to be bound to the host directories
+            # - see docker/build/README.md to view the bindings
             cp /azeroth-server/bin/worldserver /binworldserver && \
             cp /azeroth-server/bin/authserver /binauthserver

docker/database/Dockerfile

@@ -1,7 +1,9 @@
 FROM alpine:latest as builder
 
+# install bash
 RUN apk add --no-cache bash
 
+# copy the sources from the host machine
 COPY apps /azerothcore/apps
 COPY bin /azerothcore/bin
 COPY conf /azerothcore/conf
@@ -9,10 +11,14 @@ COPY data /azerothcore/data
 COPY deps /azerothcore/deps
 COPY acore.json /azerothcore/acore.json
 
+# run the AzerothCore database assembler
 RUN ./azerothcore/bin/acore-db-asm 1
 
 FROM mysql:5.7
 
+# copy files from the previous build stage - see: https://docs.docker.com/develop/develop-images/multistage-build/
 COPY --from=builder /azerothcore/env/dist/sql /sql
 
+# adding the "generate-databases.sh" to the directory "/docker-entrypoint-initdb.d"
+# because all scripts included in that directory will automatically be executed when the docker container starts
 ADD docker/database/generate-databases.sh /docker-entrypoint-initdb.d

docker/worldserver/Dockerfile

@@ -1,5 +1,7 @@
 FROM ubuntu:bionic
 
+# install the required dependencies to run the authserver
 RUN apt update && apt install -y libmysqlclient-dev libssl-dev libace-6.* libace-dev libreadline-dev;
 
+# run the worldserver located in the directory "docker/worldserver/bin" of the host machine
 CMD ["/azeroth-server/bin/worldserver"]