prosody: add LDAP authentication via SASL mechanism

prosody/Dockerfile

@@ -7,18 +7,31 @@ ADD https://raw.githubusercontent.com/jitsi/jitsi-meet/fc129d9849ca5e26245d54df6
 RUN sed -i s/hook/hook_global/g /prosody-plugins/mod_auth_token.lua
 
 RUN \
-	apt-dpkg-wrap apt-get update && \
-	apt-dpkg-wrap apt-get install -y lua5.2 liblua5.2-dev libssl1.0-dev lua-basexx luarocks gcc git && \
-	apt-dpkg-wrap apt-get install -t stretch-backports -y prosody && \
-	rm -rf /etc/prosody
-
-RUN \
-	luarocks install lua-cjson 2.1.0-1 && \
-	luarocks install luajwtjitsi
-
-RUN \
-	apt-dpkg-wrap apt-get remove -y liblua5.2-dev libssl1.0-dev gcc git && \
-	apt-cleanup
+    apt-dpkg-wrap apt-get update \
+    && apt-dpkg-wrap apt-get install -t stretch-backports -y \
+      prosody \
+      liblua5.2-dev \
+      sasl2-bin \
+      libsasl2-modules-ldap \
+      libsasl2-dev \
+      libssl1.0-dev \
+      lua-basexx \
+      lua-ldap \
+      luarocks \
+      git \
+      gcc \
+    && luarocks install cyrussasl 1.1.0-1 \
+    && luarocks install lua-cjson 2.1.0-1 \
+    && luarocks install luajwtjitsi 1.3-7 \
+    && apt-dpkg-wrap apt-get remove -t stretch-backports -y \
+      git \
+      gcc \
+      luarocks \
+      libsasl2-dev \
+      libssl1.0-dev \
+      liblua5.2-dev \
+    && apt-cleanup \
+    && rm -rf /etc/prosody
 
 COPY rootfs/ /