Update pool parameters for crystal (#3209)

frameworks/Crystal/crystal/server.cr

@@ -3,7 +3,7 @@ require "json"
 require "pg"
 require "ecr"
 
-APPDB = DB.open("postgres://benchmarkdbuser:benchmarkdbpass@#{ENV["DBHOST"]? || "127.0.0.1"}/hello_world")
+APPDB = DB.open("postgres://benchmarkdbuser:benchmarkdbpass@#{ENV["DBHOST"]? || "127.0.0.1"}/hello_world?initial_pool_size=256&max_pool_size=256&max_idle_pool_size=256")
 ID_MAXIMUM = 10_000
 
 server = HTTP::Server.new("0.0.0.0", 8080) do |context|
@@ -95,4 +95,4 @@ private def sanitized_query_count(request)
   queries.clamp(1..500)
 end
 
-server.listen(reuse_port: true)
+server.listen(reuse_port: true)