Switched to redis/postgres, major refactoring

- loginMetadata is passed to shards through redis now
- shards announce they're alive via redis.AnnounceShard() which just
  populates a hashset keyed 'shards'
- login servers grab the 'shards' hashset and randomly picks a shard to
  pass the player to (for now)
- ./service shard && ./service login
- Many new environment variables, check config/config.go for more info.
  or for a tl;dr just read the Dockerfile for the required ones
- Shard and login services now run in different processes ! (and
  containers?? wooaaah)

config/config.go

@@ -1,5 +1,21 @@
 package config
 
+import (
+	"os"
+	"time"
+)
+
+/*
+	Available environment variables:
+		REDIS_ADDR
+		REDIS_USER
+		REDIS_PASS
+		DB_ADDR
+		DB_USER
+		DB_PASS
+		ANNOUNCE_IP
+*/
+
 const (
 	AEQUIP_COUNT = 9
 	AINVEN_COUNT = 50
@@ -15,9 +31,49 @@ var (
 
 	LOGIN_PORT = 23000
 	SHARD_PORT = 23001
-	SHARD_IP   = "127.0.0.1"
+
+	LOGIN_TIMEOUT = time.Second * 30
 )
 
+func getEnv(key string, fallback string) string {
+	if value, ok := os.LookupEnv(key); ok {
+		return value
+	}
+
+	return fallback
+}
+
 func GetMaxHP(level int) int {
 	return (925 + 75*(level))
 }
+
+func GetRedisAddr() string {
+	return getEnv("REDIS_ADDR", "localhost:6379")
+}
+
+func GetRedisCredentials() func() (string, string) {
+	return func() (string, string) {
+		return getEnv("REDIS_USER", ""), getEnv("REDIS_PASS", "")
+	}
+}
+
+func GetDBName() string {
+	return getEnv("DB_NAME", "postgres")
+}
+
+func GetDBAddr() string {
+	return getEnv("DB_ADDR", "localhost:5432")
+}
+
+func GetDBUser() string {
+	return getEnv("DB_USER", "postgres")
+}
+
+func GetDBPass() string {
+	return getEnv("DB_PASS", "")
+}
+
+// needed for shard
+func GetAnnounceIP() string {
+	return getEnv("ANNOUNCE_IP", "127.0.0.1")
+}