Fix macro syntax bug in app templates

tmpl/dev.yml

@@ -1,4 +1,4 @@
-app_name: "{{app_name}} Development"
+app_name: "{% app_name %} Development"
 host_port: 0.0.0.0:8080
 web_ui: true
 
@@ -48,7 +48,7 @@ migrations_path: ./config/migrations
 auth:
   # Can be 'rails' or 'jwt'
   type: rails
-  cookie: _{{app_name_slug}}_session
+  cookie: _{% app_name_slug %}_session
 
   # Comment this out if you want to disable setting
   # the user_id via a header for testing. 
@@ -84,7 +84,7 @@ database:
   type: postgres
   host: db
   port: 5432
-  dbname: {{app_name_slug}}_development
+  dbname: {% app_name_slug %}_development
   user: postgres
   password: ''
 

tmpl/prod.yml

@@ -2,7 +2,7 @@
 # so I only need to overwrite some values
 inherits: dev
 
-app_name: "{{app_name}} Production"
+app_name: "{% app_name %} Production"
 host_port: 0.0.0.0:8080
 web_ui: false
 
@@ -47,7 +47,7 @@ enable_tracing: true
 auth: 
   # Can be 'rails' or 'jwt'
   type: rails
-  cookie: _{{app_name_slug}}_session
+  cookie: _{% app_name_slug %}_session
 
   rails:
     # Rails version this is used for reading the
@@ -78,7 +78,7 @@ database:
   type: postgres
   host: db
   port: 5432
-  dbname: {{app_name_slug}}_development
+  dbname: {% app_name_slug %}_development
   user: postgres
   password: ''
   #pool_size: 10