Fix CentOS 6 and CentOS 7

CHANGELOG.md

@@ -3,6 +3,8 @@
 * Linux distribution support
     * Arch Linux
     * Bodhi 5.0.0
+    * CentOS 6
+    * CentOS 7
     * Debian 9 
     * Elementary OS 5.0
     * Fedora 28

README.md

@@ -12,6 +12,8 @@ Repertory allows you to mount Sia and/or SiaPrime blockchain storage solutions v
 * Linux 64-bit Distributions:
     * Arch Linux
     * Bodhi 5.0.0
+    * CentOS 7
+    * CentOS 6
     * Debian 9 
     * Elementary OS 5.0
     * Fedora 28

public/detect_linux.sh

@@ -8,7 +8,18 @@ function resetDistVer {
   DISTVER=
 }
 
-if [ -f /etc/fedora-release ]; then
+if [ -f /etc/centos-release ]; then
+  . /etc/os-release
+  if [ "$VERSION_ID" == "7" ]; then
+    DISTNAME=centos
+    DISTVER=7
+  elif [ "$VERSION_ID" == "6" ]; then
+    DISTNAME=centos
+    DISTVER=6
+  else
+    resetDistVer
+  fi
+elif [ -f /etc/fedora-release ]; then
   . /etc/os-release
   if [ "$VERSION_ID" == "29" ]; then
     DISTNAME=fedora