docker-compose exec needs a -T flag it no TTY is allocated

This flag is missing in 00_create_users.sh and is failing the tests on travis arm architecture

tests/compose/core/00_create_users.sh

@@ -1,11 +1,11 @@
 echo "Users tests ..."
 # Should fail, admin is already auto-created
-docker-compose -f tests/compose/core/docker-compose.yml exec admin flask mailu admin admin mailu.io 'FooBar' && exit 1
+docker-compose -f tests/compose/core/docker-compose.yml exec -T admin flask mailu admin admin mailu.io 'FooBar' && exit 1
 echo "The above error was intended!"
 # Should not fail, but does nothing; ifmissing mode
-docker-compose -f tests/compose/core/docker-compose.yml exec admin flask mailu admin admin mailu.io 'FooBar' --mode=ifmissing || exit 1
+docker-compose -f tests/compose/core/docker-compose.yml exec -T admin flask mailu admin admin mailu.io 'FooBar' --mode=ifmissing || exit 1
 # Should not fail and update the password; update mode
-docker-compose -f tests/compose/core/docker-compose.yml exec admin flask mailu admin admin mailu.io 'password' --mode=update || exit 1
-docker-compose -f tests/compose/core/docker-compose.yml exec admin flask mailu user user mailu.io 'password' 'SHA512-CRYPT' || exit 1
-docker-compose -f tests/compose/core/docker-compose.yml exec admin flask mailu user 'user/with/slash' mailu.io 'password' 'SHA512-CRYPT' || exit 1
+docker-compose -f tests/compose/core/docker-compose.yml exec -T admin flask mailu admin admin mailu.io 'password' --mode=update || exit 1
+docker-compose -f tests/compose/core/docker-compose.yml exec -T admin flask mailu user user mailu.io 'password' 'SHA512-CRYPT' || exit 1
+docker-compose -f tests/compose/core/docker-compose.yml exec -T admin flask mailu user 'user/with/slash' mailu.io 'password' 'SHA512-CRYPT' || exit 1
 echo "User testing succesfull!"