patch Etherpad to support InnoDB

Dockerfile

@@ -6,6 +6,8 @@ WORKDIR /app
 RUN tar zxvf etherpad-lite-1.8.6.tar.gz --strip 1 -C /app && \
   rm /app/etherpad-lite-1.8.6.tar.gz
 RUN /app/bin/installDeps.sh
+COPY ./mysql_innodb.patch /app/mysql_innodb.patch
+RUN patch src/node_modules/ueberdb2/databases/mysql_db.js < mysql_innodb.patch
 COPY ./settings.json.tmpl /app/settings.json.tmpl
 COPY ./docker-entrypoint.sh /docker-entrypoint.sh
 COPY ./nginx/default.conf.tmpl /etc/nginx/conf.d/default.conf.tmpl

mysql_innodb.patch

+--- src/node_modules/ueberdb2/databases/mysql_db.js.orig
++++ src/node_modules/ueberdb2/databases/mysql_db.js
+@@ -41,7 +41,9 @@
+   if(this.settings.charset != null)
+     this.db.charset = this.settings.charset;
+ 
+-  this.settings.engine = "MyISAM"
++  if(this.settings.engine == null)
++    this.settings.engine = "MyISAM";
++
+   this.settings.cache = 1000;
+   this.settings.writeInterval = 100;
+   this.settings.json = true;