• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

When a field is defined as timestamp (or any other alternatives, like timestamptz), the precision in the database type is always 0 (regardless if a precision was specified or not).

Expected Behavior 🤔

When no precision is specified, the database type shouldn't have a precision.
When a precision is specified, the database type should have that precision, not zero.

Steps to Reproduce 🕹

Steps:

1. Create a time field
2. Enable atlas
3. Describe the table

var timeSchema = map[string]string{
	dialect.Postgres: "timestamptz",
	dialect.SQLite:   "timestamp",
	dialect.MySQL:    "datetime(3)",
}

// ...

field.Time("expiry").
    SchemaType(timeSchema),

Your Environment 🌎

I was able to reproduce the issue in this PR: dexidp/dex#2428

One additional detail (that should probably end up in a separate issue): even when Atlas is disabled, precision values are ignored. Even if I set the type to timestamptz(3) for example, in the database the type will just be timestamp with time zone. This is fine in my case because the default is not zero fortunately.