Improve Dockerized Test Deployment documentation (#1179)

* Improve Dockerized Test Deployment documentation

* Add curly brackets to align with other variables

trillian/examples/deployment/docker/ctfe/README.md

@@ -13,9 +13,19 @@ serving production logs!
   - github.com/google/certificate-transparency-go
 
 The instructions below assume you've checked out the repositories within
-`~/git/`, but if you have them in another location then just use a different
+`/workspaces/`, but if you have them in another location then just use a different
 path when you run the command.
 
+```bash
+# Terminal 1
+export GIT_HOME=/workspaces
+```
+
+```bash
+# Terminal 2
+export GIT_HOME=/workspaces
+```
+
 ## Deploying
 
 We will use 2 terminal sessions to the machine you will use for hosting the
@@ -27,16 +37,16 @@ First bring up the trillian instance and the database:
 
 ```bash
 # Terminal 1
-cd ~/git/certificate-transparency-go/trillian/examples/deployment/docker/ctfe/
+cd ${GIT_HOME}/certificate-transparency-go/trillian/examples/deployment/docker/ctfe/
 docker compose up
 ```
 
 This brings up everything except the CTFE. Now to provision the logs.
 
 ```bash
 # Terminal 2
-cd ~/git/trillian/
-docker exec -i ctfe-db mysql -pzaphod -Dtest < ./storage/mysql/schema/storage.sql
+cd ${GIT_HOME}/trillian/
+docker exec -i ctfe-db mariadb -pzaphod -Dtest < ./storage/mysql/schema/storage.sql
 ```
 
 The CTFE requires some configuration files. First prepare a directory containing
@@ -49,8 +59,8 @@ more than a few hours then pick a less temporary location on your filesystem.
 CTFE_CONF_DIR=/tmp/ctfedocker
 mkdir ${CTFE_CONF_DIR}
 TREE_ID=$(go run github.com/google/trillian/cmd/createtree@master --admin_server=localhost:8090)
-sed "s/@TREE_ID@/$TREE_ID/" ~/git/certificate-transparency-go/trillian/examples/deployment/docker/ctfe/ct_server.cfg > ${CTFE_CONF_DIR}/ct_server.cfg
-cp ./trillian/testdata/fake-ca.cert ${CTFE_CONF_DIR}
+sed "s/@TREE_ID@/${TREE_ID}/" ${GIT_HOME}/certificate-transparency-go/trillian/examples/deployment/docker/ctfe/ct_server.cfg > ${CTFE_CONF_DIR}/ct_server.cfg
+cp ${GIT_HOME}/certificate-transparency-go/trillian/testdata/fake-ca.cert ${CTFE_CONF_DIR}
 docker volume create --driver local --opt type=none --opt device=${CTFE_CONF_DIR} --opt o=bind ctfe_config
 ```
 
@@ -67,7 +77,6 @@ then the following command should return tree head for tree size 0.
 
 ```bash
 # Terminal 2
-cd ~/git/certificate-transparency-go
+cd ${GIT_HOME}/certificate-transparency-go
 go run ./client/ctclient get-sth --log_uri http://localhost:8080/testlog
 ```
-