feat: Add optional config of database connection pooling

.env.sample

@@ -12,6 +12,8 @@ UTILS_SECRET=generate_a_new_key
 # should work out of the box.
 DATABASE_URL=postgres://user:pass@localhost:5432/outline
 DATABASE_URL_TEST=postgres://user:pass@localhost:5432/outline-test
+DATABASE_CONNECTION_POOL_MIN=
+DATABASE_CONNECTION_POOL_MAX=
 # Uncomment this to disable SSL for connecting to Postgres
 # PGSSLMODE=disable
 REDIS_URL=redis://localhost:6379

server/database/sequelize.ts

@@ -4,6 +4,8 @@ import * as models from "../models";
 
 const isProduction = process.env.NODE_ENV === "production";
 const isSSLDisabled = process.env.PGSSLMODE === "disable";
+const poolMax = parseInt(process.env.DATABASE_CONNECTION_POOL_MAX || "5", 10);
+const poolMin = parseInt(process.env.DATABASE_CONNECTION_POOL_MIN || "0", 10);
 
 export const sequelize = new Sequelize(
   process.env.DATABASE_URL || process.env.DATABASE_CONNECTION_POOL_URL || "",
@@ -20,5 +22,11 @@ export const sequelize = new Sequelize(
           : false,
     },
     models: Object.values(models),
+    pool: {
+      max: poolMax,
+      min: poolMin,
+      acquire: 30000,
+      idle: 10000,
+    },
   }
 );