diff --git a/Dockerfile b/Dockerfile
index 13c8fb5..6c6ee7a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,22 +1,26 @@
 FROM docker.jcg.re/base-alpine
-MAINTAINER Jan Christian Grünhage <jan.christian@gruenhage.xyz>
 
-ENV	UID=192 \
-	GID=192
+RUN apk add --no-cache \
+      --virtual .build-deps \
+      git \
+      python3-dev \
+      libffi-dev \
+      build-base \
+      openssl-dev \
+ && apk add --no-cache \
+      --virtual .runtime-deps \
+      openssl \
+      curl \
+      sed \
+      grep \
+      bash \
+      su-exec \
+      libxml2-utils \
+ && git clone https://github.com/lukas2511/dehydrated /dehydrated \
+ && pip3 install requests[security] \
+ && pip3 install dns-lexicon \
+ && apk del .build-deps
 
-RUN apk update \
-	&& apk add --upgrade \
-		git \
-		openssl \
-		curl \
-		sed \
-		grep \
-		bash \
-		su-exec \
-		libxml2-utils \
-	&& git clone https://github.com/lukas2511/dehydrated /dehydrated
-
-# Add the files in the 'root' folder to the images filesystem
 ADD root /
 
 VOLUME /etc/dehydrated
diff --git a/root/usr/local/bin/lexicon-hook b/root/usr/local/bin/lexicon-hook
new file mode 100755
index 0000000..dacb64a
--- /dev/null
+++ b/root/usr/local/bin/lexicon-hook
@@ -0,0 +1,130 @@
+#!/usr/bin/env bash
+#
+# Example how to deploy a DNS challenge using lexicon
+
+set -e
+set -u
+set -o pipefail
+
+export PROVIDER=${PROVIDER:-"cloudflare"}
+
+function deploy_challenge {
+    local DOMAIN="${1}" TOKEN_FILENAME="${2}" TOKEN_VALUE="${3}"
+
+    echo "deploy_challenge called: ${DOMAIN}, ${TOKEN_FILENAME}, ${TOKEN_VALUE}"
+
+    lexicon $PROVIDER create ${DOMAIN} TXT --name="_acme-challenge.${DOMAIN}." --content="${TOKEN_VALUE}"
+
+    sleep 30
+
+    # This hook is called once for every domain that needs to be
+    # validated, including any alternative names you may have listed.
+    #
+    # Parameters:
+    # - DOMAIN
+    #   The domain name (CN or subject alternative name) being
+    #   validated.
+    # - TOKEN_FILENAME
+    #   The name of the file containing the token to be served for HTTP
+    #   validation. Should be served by your web server as
+    #   /.well-known/acme-challenge/${TOKEN_FILENAME}.
+    # - TOKEN_VALUE
+    #   The token value that needs to be served for validation. For DNS
+    #   validation, this is what you want to put in the _acme-challenge
+    #   TXT record. For HTTP validation it is the value that is expected
+    #   be found in the $TOKEN_FILENAME file.
+}
+
+function clean_challenge {
+    local DOMAIN="${1}" TOKEN_FILENAME="${2}" TOKEN_VALUE="${3}"
+
+    echo "clean_challenge called: ${DOMAIN}, ${TOKEN_FILENAME}, ${TOKEN_VALUE}"
+
+    lexicon $PROVIDER delete ${DOMAIN} TXT --name="_acme-challenge.${DOMAIN}." --content="${TOKEN_VALUE}"
+
+    # This hook is called after attempting to validate each domain,
+    # whether or not validation was successful. Here you can delete
+    # files or DNS records that are no longer needed.
+    #
+    # The parameters are the same as for deploy_challenge.
+}
+
+function invalid_challenge() {
+    local DOMAIN="${1}" RESPONSE="${2}"
+
+    echo "invalid_challenge called: ${DOMAIN}, ${RESPONSE}"
+
+    # This hook is called if the challenge response has failed, so domain
+    # owners can be aware and act accordingly.
+    #
+    # Parameters:
+    # - DOMAIN
+    #   The primary domain name, i.e. the certificate common
+    #   name (CN).
+    # - RESPONSE
+    #   The response that the verification server returned
+}
+
+function deploy_cert {
+    local DOMAIN="${1}" KEYFILE="${2}" CERTFILE="${3}" FULLCHAINFILE="${4}" CHAINFILE="${5}"
+
+    echo "deploy_cert called: ${DOMAIN}, ${KEYFILE}, ${CERTFILE}, ${FULLCHAINFILE}, ${CHAINFILE}"
+
+    # This hook is called once for each certificate that has been
+    # produced. Here you might, for instance, copy your new certificates
+    # to service-specific locations and reload the service.
+    #
+    # Parameters:
+    # - DOMAIN
+    #   The primary domain name, i.e. the certificate common
+    #   name (CN).
+    # - KEYFILE
+    #   The path of the file containing the private key.
+    # - CERTFILE
+    #   The path of the file containing the signed certificate.
+    # - FULLCHAINFILE
+    #   The path of the file containing the full certificate chain.
+    # - CHAINFILE
+    #   The path of the file containing the intermediate certificate(s).
+}
+
+function unchanged_cert {
+    local DOMAIN="${1}" KEYFILE="${2}" CERTFILE="${3}" FULLCHAINFILE="${4}" CHAINFILE="${5}"
+
+    echo "unchanged_cert called: ${DOMAIN}, ${KEYFILE}, ${CERTFILE}, ${FULLCHAINFILE}, ${CHAINFILE}"
+
+    # This hook is called once for each certificate that is still
+    # valid and therefore wasn't reissued.
+    #
+    # Parameters:
+    # - DOMAIN
+    #   The primary domain name, i.e. the certificate common
+    #   name (CN).
+    # - KEYFILE
+    #   The path of the file containing the private key.
+    # - CERTFILE
+    #   The path of the file containing the signed certificate.
+    # - FULLCHAINFILE
+    #   The path of the file containing the full certificate chain.
+    # - CHAINFILE
+    #   The path of the file containing the intermediate certificate(s).
+}
+
+exit_hook() {
+  # This hook is called at the end of a dehydrated command and can be used
+  # to do some final (cleanup or other) tasks.
+
+  :
+}
+
+startup_hook() {
+  # This hook is called before the dehydrated command to do some initial tasks
+  # (e.g. starting a webserver).
+
+  :
+}
+
+HANDLER=$1; shift;
+if [ -n "$(type -t $HANDLER)" ] && [ "$(type -t $HANDLER)" = function ]; then
+  $HANDLER "$@"
+fi