Update Docker files and remove references to gb (#703)

Fix Docker files which had been forgotten in #594 and update scripts and docs to remove references to gb.

I also removed the `jenkins` directory which is outdated. We can revert f8d7e99 if we realise that it was a mistake to do so.

docker/Dockerfile

@@ -1,10 +1,9 @@
-FROM golang:alpine3.6
+FROM docker.io/golang:1.12.5-alpine3.9
 
 RUN mkdir /build
 
 WORKDIR /build
 
-RUN apk --update --no-cache add openssl bash git && \
-    go get github.com/constabulary/gb/...
+RUN apk --update --no-cache add openssl bash git
 
 CMD ["bash", "docker/build.sh"]

docker/build.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-gb build
+./build.sh
 
 # Generate the keys if they don't already exist.
 if [ ! -f server.key ] || [ ! -f server.crt ] || [ ! -f matrix_key.pem ]; then
@@ -12,7 +12,7 @@ if [ ! -f server.key ] || [ ! -f server.crt ] || [ ! -f matrix_key.pem ]; then
                         -keyout server.key \
                         -out server.crt \
                         -days 3650 -nodes \
-                        -subj /CN=localhost 
+                        -subj /CN=localhost
 
     test -f matrix_key.pem || /build/bin/generate-keys -private-key matrix_key.pem
 fi

docker/docker-compose.yml

@@ -7,7 +7,6 @@ services:
     build: ./
     volumes:
       - ..:/build
-      - ./build/pkg:/build/pkg
       - ./build/bin:/build/bin
     networks:
       - internal