replace do_postgres with pg for better timestamps

do_postgres is using DateTime to fetch timestamps which results in
loosing the milliseconds. But we need the exact timestamp to fetch the
previous and next posts.

Gemfile

@@ -1,7 +1,7 @@
 source 'https://rubygems.org'
 
 gem 'sequel'
-gem 'do_postgres'
+gem 'pg'
 gem 'zero', :git => 'https://github.com/libzero/zero.git'
 gem 'slim'
 gem 'sass'

Gemfile.lock

@@ -1,6 +1,6 @@
 GIT
   remote: https://github.com/libzero/zero.git
-  revision: 06b851bd4f90109eae4bda8f9b69c60b221f6275
+  revision: dde9fc410fb50bc44b128fb1032b15f09c53e0f7
   specs:
     zero (0.2.0)
       tilt
@@ -8,18 +8,13 @@ GIT
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.3.5)
-    data_objects (0.10.13)
-      addressable (~> 2.1)
-    do_postgres (0.10.13)
-      data_objects (= 0.10.13)
     ffi2-generators (0.1.1)
-    kramdown (1.2.0)
+    kramdown (1.3.0)
-    minitest (4.7.5)
+    pg (0.17.1)
-    puma (2.6.0)
+    puma (2.7.1)
       rack (>= 1.1, < 2.0)
     rack (1.5.2)
-    rubysl (2.0.11)
+    rubysl (2.0.15)
       rubysl-abbrev (~> 2.0)
       rubysl-base64 (~> 2.0)
       rubysl-benchmark (~> 2.0)
@@ -54,7 +49,6 @@ GEM
       rubysl-io-wait (~> 2.0)
       rubysl-ipaddr (~> 2.0)
       rubysl-irb (~> 2.0)
-      rubysl-json (~> 2.0)
       rubysl-logger (~> 2.0)
       rubysl-mathn (~> 2.0)
       rubysl-matrix (~> 2.0)
@@ -87,7 +81,6 @@ GEM
       rubysl-resolv (~> 2.0)
       rubysl-rexml (~> 2.0)
       rubysl-rinda (~> 2.0)
-      rubysl-ripper (~> 2.0)
       rubysl-rss (~> 2.0)
       rubysl-scanf (~> 2.0)
       rubysl-securerandom (~> 2.0)
@@ -97,15 +90,14 @@ GEM
       rubysl-socket (~> 2.0)
       rubysl-stringio (~> 2.0)
       rubysl-strscan (~> 2.0)
+      rubysl-sync (~> 2.0)
       rubysl-syslog (~> 2.0)
       rubysl-tempfile (~> 2.0)
-      rubysl-test-unit (~> 2.0)
       rubysl-thread (~> 2.0)
       rubysl-thwait (~> 2.0)
       rubysl-time (~> 2.0)
       rubysl-timeout (~> 2.0)
       rubysl-tmpdir (~> 2.0)
-      rubysl-tracer (~> 2.0)
       rubysl-tsort (~> 2.0)
       rubysl-un (~> 2.0)
       rubysl-uri (~> 2.0)
@@ -114,36 +106,36 @@ GEM
       rubysl-xmlrpc (~> 2.0)
       rubysl-yaml (~> 2.0)
       rubysl-zlib (~> 2.0)
-    rubysl-abbrev (2.0.2)
+    rubysl-abbrev (2.0.4)
     rubysl-base64 (2.0.0)
-    rubysl-benchmark (2.0.0)
+    rubysl-benchmark (2.0.1)
     rubysl-bigdecimal (2.0.2)
-    rubysl-cgi (2.0.0)
+    rubysl-cgi (2.0.1)
-    rubysl-cgi-session (2.0.0)
+    rubysl-cgi-session (2.0.1)
     rubysl-cmath (2.0.0)
     rubysl-complex (2.0.0)
     rubysl-continuation (2.0.0)
     rubysl-coverage (2.0.3)
-    rubysl-csv (2.0.1)
+    rubysl-csv (2.0.2)
       rubysl-english (~> 2.0)
-    rubysl-curses (2.0.0)
+    rubysl-curses (2.0.1)
     rubysl-date (2.0.6)
-    rubysl-delegate (2.0.0)
+    rubysl-delegate (2.0.1)
-    rubysl-digest (2.0.2)
+    rubysl-digest (2.0.3)
     rubysl-drb (2.0.1)
     rubysl-e2mmap (2.0.0)
     rubysl-english (2.0.0)
     rubysl-enumerator (2.0.0)
-    rubysl-erb (2.0.0)
+    rubysl-erb (2.0.1)
     rubysl-etc (2.0.3)
       ffi2-generators (~> 0.1)
     rubysl-expect (2.0.0)
     rubysl-fcntl (2.0.4)
       ffi2-generators (~> 0.1)
     rubysl-fiber (2.0.0)
-    rubysl-fileutils (2.0.2)
+    rubysl-fileutils (2.0.3)
-    rubysl-find (2.0.0)
+    rubysl-find (2.0.1)
-    rubysl-forwardable (2.0.0)
+    rubysl-forwardable (2.0.1)
     rubysl-getoptlong (2.0.0)
     rubysl-gserver (2.0.0)
       rubysl-socket (~> 2.0)
@@ -152,13 +144,11 @@ GEM
     rubysl-io-nonblock (2.0.0)
     rubysl-io-wait (2.0.0)
     rubysl-ipaddr (2.0.0)
-    rubysl-irb (2.0.3)
+    rubysl-irb (2.0.4)
       rubysl-e2mmap (~> 2.0)
       rubysl-mathn (~> 2.0)
       rubysl-readline (~> 2.0)
       rubysl-thread (~> 2.0)
-      rubysl-tracer (~> 2.0)
-    rubysl-json (2.0.2)
     rubysl-logger (2.0.0)
     rubysl-mathn (2.0.0)
     rubysl-matrix (2.1.0)
@@ -182,13 +172,13 @@ GEM
     rubysl-observer (2.0.0)
     rubysl-open-uri (2.0.0)
     rubysl-open3 (2.0.0)
-    rubysl-openssl (2.0.1)
+    rubysl-openssl (2.0.5)
     rubysl-optparse (2.0.1)
       rubysl-shellwords (~> 2.0)
     rubysl-ostruct (2.0.4)
     rubysl-pathname (2.0.0)
-    rubysl-prettyprint (2.0.1)
+    rubysl-prettyprint (2.0.2)
-    rubysl-prime (2.0.0)
+    rubysl-prime (2.0.1)
     rubysl-profile (2.0.0)
     rubysl-profiler (2.0.1)
     rubysl-pstore (2.0.0)
@@ -196,9 +186,8 @@ GEM
     rubysl-rational (2.0.1)
     rubysl-readline (2.0.2)
     rubysl-resolv (2.0.0)
-    rubysl-rexml (2.0.1)
+    rubysl-rexml (2.0.2)
     rubysl-rinda (2.0.0)
-    rubysl-ripper (2.0.0)
     rubysl-rss (2.0.0)
     rubysl-scanf (2.0.0)
     rubysl-securerandom (2.0.0)
@@ -208,17 +197,15 @@ GEM
     rubysl-socket (2.0.1)
     rubysl-stringio (2.0.0)
     rubysl-strscan (2.0.0)
+    rubysl-sync (2.0.0)
     rubysl-syslog (2.0.1)
       ffi2-generators (~> 0.1)
     rubysl-tempfile (2.0.1)
-    rubysl-test-unit (2.0.1)
-      minitest (~> 4.7)
     rubysl-thread (2.0.2)
     rubysl-thwait (2.0.0)
     rubysl-time (2.0.3)
     rubysl-timeout (2.0.0)
     rubysl-tmpdir (2.0.0)
-    rubysl-tracer (2.0.0)
     rubysl-tsort (2.0.1)
     rubysl-un (2.0.0)
       rubysl-fileutils (~> 2.0)
@@ -227,22 +214,22 @@ GEM
     rubysl-weakref (2.0.0)
     rubysl-webrick (2.0.0)
     rubysl-xmlrpc (2.0.0)
-    rubysl-yaml (2.0.0)
+    rubysl-yaml (2.0.4)
     rubysl-zlib (2.0.1)
-    sass (3.2.12)
+    sass (3.2.13)
-    sequel (4.3.0)
+    sequel (4.5.0)
-    slim (2.0.1)
+    slim (2.0.2)
       temple (~> 0.6.6)
       tilt (>= 1.3.3, < 2.1)
     temple (0.6.7)
-    tilt (1.4.1)
+    tilt (2.0.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  do_postgres
   kramdown
+  pg
   puma
   rubysl
   sass