Add cockroach support and tests

[lunny]

[lunny]

Should fix #802

[codecov-io]

Codecov Report

Merging #896 into master will decrease coverage by 2.96%. The diff coverage is 44%.

@@            Coverage Diff             @@
##           master     #896      +/-   ##
==========================================
- Coverage   57.55%   54.58%   -2.97%     
==========================================
  Files          44       42       -2     
  Lines        7966     7661     -305     
==========================================
- Hits         4585     4182     -403     
- Misses       2818     2943     +125     
+ Partials      563      536      -27

Impacted Files	Coverage Δ
engine.go	61.35% <42.85%> (-1.24%)	:arrow_down:
dialect_postgres.go	73.5% <44.44%> (-2.46%)	:arrow_down:
dialect_mssql.go	0% <0%> (-73.81%)	:arrow_down:
session_exist.go	57.44% <0%> (-5.52%)	:arrow_down:
rows.go	50.76% <0%> (-5.38%)	:arrow_down:
session_update.go	52.22% <0%> (-4.39%)	:arrow_down:
helpers.go	57.41% <0%> (-2.32%)	:arrow_down:
tag.go	77.09% <0%> (-2.22%)	:arrow_down:
xorm.go	64.61% <0%> (-2.06%)	:arrow_down:
engine_cond.go	54.96% <0%> (-1.33%)	:arrow_down:
... and 19 more

---

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[techknowlogick]

@lunny you can use the --background flag to run cockroachdb to run in the background

[techknowlogick]

@lunny it looks like a lot of failures from the tests come from the colType being STRING(255), per postgresql docs that is not an available column type.

The following table has the available column types for text/strings:

Name	Description
character varying(n), varchar(n)	variable-length with limit
character(n), char(n)	fixed-length, blank padded
text	variable unlimited length

Here is the link to the specific docs page that I am refering to: https://www.postgresql.org/docs/9.6/static/datatype-character.html

[vtolstov]

gentle ping..

[lunny]

@vtolstov I will change this and test with the latest cockroach

[vtolstov]

@lunny do you already have tests and all works fine?

[lunny]

Will continue the work on this PR.

[vtolstov]

please unblock comments on gitea.com/xorm/xorm repo