Allow configuration of supported languages during instance gen

lib/mix/tasks/pleroma/instance.ex

@@ -23,6 +23,7 @@ def run(["gen" | rest]) do
           instance_name: :string,
           admin_email: :string,
           notify_email: :string,
+          languages: :string,
           dbhost: :string,
           dbname: :string,
           dbuser: :string,
@@ -83,6 +84,14 @@ def run(["gen" | rest]) do
           email
         )
 
+      languages =
+        get_option(
+          options,
+          :languages,
+          "Which languages do you want to support in your instance? (comma separated)",
+          "en"
+        )
+
       indexable =
         get_option(
           options,
@@ -223,6 +232,10 @@ def run(["gen" | rest]) do
           port: port,
           email: email,
           notify_email: notify_email,
+          languages:
+            languages
+            |> String.split(",", trim: true)
+            |> Enum.map(fn lang -> String.trim(lang) end),
           name: name,
           dbhost: dbhost,
           dbname: dbname,

priv/templates/sample_config.eex

@@ -21,6 +21,7 @@ config :pleroma, :instance,
   email: "<%= email %>",
   notify_email: "<%= notify_email %>",
   limit: 5000,
+  languages: <%= inspect(languages) %>,
   registrations_open: true
 
 config :pleroma, :media_proxy,